diff --git a/backend/internal/controllers/download.go b/backend/internal/controllers/download.go
index 09ea53e..edbfdb9 100644
--- a/backend/internal/controllers/download.go
+++ b/backend/internal/controllers/download.go
@@ -2,7 +2,6 @@ package controllers
 
 import (
 	"backend/internal/utils"
-	"errors"
 	"fmt"
 	"pkg/models"
 	u "pkg/utils"
@@ -21,7 +20,7 @@ type DownloadShareClaims struct {
 func DownloadShare(c *echo.Context) error {
 	token := c.FormValue("token")
 	if token == "" {
-		return utils.HTTPErrorHandler(c, errors.New("缺少token"))
+		return utils.HTTPErrorHandler(c, ErrInvalidRequest)
 	}
 	claims := DownloadShareClaims{}
 	t, err := jwt.ParseWithClaims(token, &claims, func(token *jwt.Token) (interface{}, error) {
@@ -31,7 +30,7 @@ func DownloadShare(c *echo.Context) error {
 		return utils.HTTPErrorHandler(c, err)
 	}
 	if !t.Valid {
-		return utils.HTTPErrorHandler(c, errors.New("token格式错误"))
+		return utils.HTTPErrorHandler(c, ErrInvalidRequest)
 	}
 	shareInfo, _ := models.GetRedisShareInfo(claims.ShareId)
 
@@ -60,7 +59,7 @@ func VaildateShare(c *echo.Context) error {
 	}
 
 	if r.ShareId == "" {
-		return utils.HTTPErrorHandler(c, errors.New("缺少分享ID"))
+		return utils.HTTPErrorHandler(c, ErrInvalidRequest)
 	}
 
 	shareInfo, err := models.GetRedisShareInfo(r.ShareId)
@@ -68,23 +67,23 @@ func VaildateShare(c *echo.Context) error {
 		return utils.HTTPErrorHandler(c, err)
 	}
 	if shareInfo == nil {
-		return utils.HTTPErrorHandler(c, errors.New("分享不存在"))
+		return utils.HTTPErrorHandler(c, ErrShareNotFound)
 	}
 	if shareInfo.Password != "" {
 		if r.Password == "" {
-			return utils.HTTPErrorHandler(c, errors.New("缺少分享密码"))
+			return utils.HTTPErrorHandler(c, ErrInvalidRequest)
 		}
 		hash, err := utils.GeneratePasswordHash(r.Password)
 		if err != nil {
 			return utils.HTTPErrorHandler(c, err)
 		}
 		if hash != shareInfo.Password {
-			return utils.HTTPErrorHandler(c, errors.New("分享密码错误"))
+			return utils.HTTPErrorHandler(c, ErrInvalidSharePassword)
 		}
 	}
 	// 如果下载次数为0，则设置为-1 防止空值问题
 	if shareInfo.ViewNum < 1 {
-		return utils.HTTPErrorHandler(c, errors.New("下载次数不足"))
+		return utils.HTTPErrorHandler(c, ErrInsufficientDownloadQuota)
 	}
 	downloadWindow := u.GetEnvWithDefault("share.download_window", "12")
 	token := jwt.NewWithClaims(jwt.SigningMethodHS256, DownloadShareClaims{
@@ -105,10 +104,10 @@ func VaildateShare(c *echo.Context) error {
 			return utils.HTTPErrorHandler(c, err)
 		}
 		if fileInfo == nil {
-			return utils.HTTPErrorHandler(c, errors.New("分享文件不存在"))
+			return utils.HTTPErrorHandler(c, ErrShareFileNotFound)
 		}
 		if fileInfo.FileType != models.FileTypeUpload {
-			return utils.HTTPErrorHandler(c, errors.New("分享文件状态错误"))
+			return utils.HTTPErrorHandler(c, ErrInvalidShareFileState)
 		}
 	}
 	// download_nums 必须放在创建token的时候减掉，不然多线程下载会导致多次减掉
diff --git a/backend/internal/controllers/errors.go b/backend/internal/controllers/errors.go
new file mode 100644
index 0000000..bd290dc
--- /dev/null
+++ b/backend/internal/controllers/errors.go
@@ -0,0 +1,30 @@
+package controllers
+
+import "errors"
+
+var (
+	// 通用错误（参数校验失败）
+	ErrInvalidRequest = errors.New("InvalidRequest") // 调用接口参数错误
+
+	// 任务相关
+	ErrTaskNotFound = errors.New("TaskNotFound") // 任务不存在
+	ErrTaskExpired  = errors.New("TaskExpired")  // 任务已过期
+
+	// 文件上传相关
+	ErrInsufficientStorage    = errors.New("InsufficientStorage")    // 存储空间不足
+	ErrUploadTaskExpired      = errors.New("UploadTaskExpired")      // 上传任务已过期
+	ErrInvalidUploadTaskState = errors.New("InvalidUploadTaskState") // 上传任务状态错误
+	ErrInvalidFileSliceIndex  = errors.New("InvalidFileSliceIndex")  // 文件切片索引错误
+	ErrInvalidFileSliceSize   = errors.New("InvalidFileSliceSize")   // 文件切片大小错误
+	ErrIncompleteFileSlices   = errors.New("IncompleteFileSlices")   // 文件切片不完整
+	ErrFileMD5Mismatch        = errors.New("FileMD5Mismatch")        // 文件MD5不一致
+
+	// 分享相关
+	ErrShareFileNotFound     = errors.New("ShareFileNotFound")     // 分享文件不存在
+	ErrInvalidShareFileState = errors.New("InvalidShareFileState") // 分享文件状态错误
+	ErrShareNotFound         = errors.New("ShareNotFound")         // 分享不存在
+
+	// 下载相关
+	ErrInvalidSharePassword      = errors.New("InvalidSharePassword")      // 分享密码错误
+	ErrInsufficientDownloadQuota = errors.New("InsufficientDownloadQuota") // 下载次数不足
+)
diff --git a/backend/internal/controllers/file.go b/backend/internal/controllers/file.go
index 63e5eb0..0fb27d5 100644
--- a/backend/internal/controllers/file.go
+++ b/backend/internal/controllers/file.go
@@ -4,7 +4,6 @@ import (
 	"backend/internal/services"
 	"backend/internal/utils"
 	"encoding/json"
-	"errors"
 	"math"
 	"mime/multipart"
 	"os"
@@ -25,7 +24,7 @@ func CreateUploadTask(c *echo.Context) error {
 	}
 
 	if r.FileSize == 0 || r.MimeType == "" || r.FileHash == "" {
-		return utils.HTTPErrorHandler(c, errors.New("调用接口参数错误"))
+		return utils.HTTPErrorHandler(c, ErrInvalidRequest)
 	}
 	fileId := u.GetFileId(r.FileHash, r.FileSize)
 	fileInfo, err := models.GetRedisFileInfo(fileId)
@@ -71,7 +70,7 @@ func CreateUploadTask(c *echo.Context) error {
 		totalSize += fileInfo.FileSize
 	}
 	if totalSize+r.FileSize > int64(maxStorageSize) {
-		return utils.HTTPErrorHandler(c, errors.New("存储空间不足"))
+		return utils.HTTPErrorHandler(c, ErrInsufficientStorage)
 	}
 
 	ChunkSize := int64(0.25 * 1024 * 1024)
@@ -125,7 +124,7 @@ func UploadFileSlice(c *echo.Context) error {
 	}
 
 	if r.FileId == "" || r.FileIndex == 0 || r.FileSlice == nil {
-		return utils.HTTPErrorHandler(c, errors.New("调用接口参数错误"))
+		return utils.HTTPErrorHandler(c, ErrInvalidRequest)
 	}
 	fileInfo, err := models.GetRedisFileInfo(r.FileId)
 	if err != nil {
@@ -134,18 +133,18 @@ func UploadFileSlice(c *echo.Context) error {
 
 	now := time.Now().Unix()
 	if fileInfo.CreatedAt+fileInfo.Expire < now {
-		return utils.HTTPErrorHandler(c, errors.New("上传任务已过期"))
+		return utils.HTTPErrorHandler(c, ErrUploadTaskExpired)
 	}
 
 	if fileInfo.FileType != models.FileTypeInit {
-		return utils.HTTPErrorHandler(c, errors.New("上传任务状态错误"))
+		return utils.HTTPErrorHandler(c, ErrInvalidUploadTaskState)
 	}
 	if r.FileIndex > ((fileInfo.FileSize / fileInfo.ChunkSize) + 1) {
-		return utils.HTTPErrorHandler(c, errors.New("文件切片索引错误"))
+		return utils.HTTPErrorHandler(c, ErrInvalidFileSliceIndex)
 	}
 
 	if r.FileSlice.Size > fileInfo.ChunkSize {
-		return utils.HTTPErrorHandler(c, errors.New("文件切片大小错误"))
+		return utils.HTTPErrorHandler(c, ErrInvalidFileSliceSize)
 	}
 
 	// 打开文件
@@ -180,7 +179,7 @@ func FinishUploadTask(c *echo.Context) error {
 	}
 
 	if r.FileId == "" {
-		return utils.HTTPErrorHandler(c, errors.New("文件ID不能为空"))
+		return utils.HTTPErrorHandler(c, ErrInvalidRequest)
 	}
 
 	fileInfo, err := models.GetRedisFileInfo(r.FileId)
@@ -189,12 +188,12 @@ func FinishUploadTask(c *echo.Context) error {
 	}
 
 	if fileInfo.FileType != models.FileTypeInit {
-		return utils.HTTPErrorHandler(c, errors.New("上传任务状态错误"))
+		return utils.HTTPErrorHandler(c, ErrInvalidUploadTaskState)
 	}
 
 	now := time.Now().Unix()
 	if fileInfo.CreatedAt+fileInfo.Expire < now {
-		return utils.HTTPErrorHandler(c, errors.New("上传任务已过期"))
+		return utils.HTTPErrorHandler(c, ErrUploadTaskExpired)
 	}
 
 	uploadPath, err := u.GetUploadDirPath()
@@ -208,7 +207,7 @@ func FinishUploadTask(c *echo.Context) error {
 	}
 
 	if len(fileSliceList) != int(math.Ceil(float64(fileInfo.FileSize)/float64(fileInfo.ChunkSize))) {
-		return utils.HTTPErrorHandler(c, errors.New("文件切片不完整"))
+		return utils.HTTPErrorHandler(c, ErrIncompleteFileSlices)
 	}
 
 	// 最终合并后的文件路径
@@ -236,7 +235,7 @@ func FinishUploadTask(c *echo.Context) error {
 	if file_hash != fileInfo.FileHash {
 		file.Close()
 		os.Remove(mergeFilePath)
-		return utils.HTTPErrorHandler(c, errors.New("文件MD5不一致"))
+		return utils.HTTPErrorHandler(c, ErrFileMD5Mismatch)
 	}
 	defer file.Close()
 	// 更新文件信息
diff --git a/backend/internal/controllers/share.go b/backend/internal/controllers/share.go
index b6a6426..3103820 100644
--- a/backend/internal/controllers/share.go
+++ b/backend/internal/controllers/share.go
@@ -3,7 +3,6 @@ package controllers
 import (
 	"backend/internal/utils"
 	"encoding/json"
-	"errors"
 	"pkg/models"
 	u "pkg/utils"
 	"strings"
@@ -41,11 +40,11 @@ func CreateShareInfo(c *echo.Context) error {
 		return utils.HTTPErrorHandler(c, err)
 	}
 	if r.Config.ExpireAt < 1 {
-		return utils.HTTPErrorHandler(c, errors.New("非法的分享过期时间"))
+		return utils.HTTPErrorHandler(c, ErrInvalidRequest)
 	}
 	ExpireTime := time.Now().Add(time.Duration(r.Config.ExpireAt) * time.Minute)
 	if r.Data == "" || (r.Type != models.ShareTypeFile && r.Type != models.ShareTypeText) || ExpireTime.Before(time.Now()) || r.Config.ViewNum < 1 {
-		return utils.HTTPErrorHandler(c, errors.New("调用接口参数错误"))
+		return utils.HTTPErrorHandler(c, ErrInvalidRequest)
 	}
 
 	id, err := gonanoid.New()
@@ -59,10 +58,10 @@ func CreateShareInfo(c *echo.Context) error {
 			return utils.HTTPErrorHandler(c, err)
 		}
 		if fileInfo == nil {
-			return utils.HTTPErrorHandler(c, errors.New("分享文件不存在"))
+			return utils.HTTPErrorHandler(c, ErrShareFileNotFound)
 		}
 		if fileInfo.FileType != models.FileTypeUpload {
-			return utils.HTTPErrorHandler(c, errors.New("分享文件状态错误"))
+			return utils.HTTPErrorHandler(c, ErrInvalidShareFileState)
 		}
 	}
 	password := ""
@@ -151,7 +150,7 @@ type GetShareProps struct {
 func GetShareInfo(c *echo.Context) error {
 	shareId := c.Param("id")
 	if shareId == "" {
-		return utils.HTTPErrorHandler(c, errors.New("缺少分享ID"))
+		return utils.HTTPErrorHandler(c, ErrInvalidRequest)
 	}
 
 	shareInfo, err := models.GetRedisShareInfo(shareId)
@@ -159,7 +158,7 @@ func GetShareInfo(c *echo.Context) error {
 		return utils.HTTPErrorHandler(c, err)
 	}
 	if shareInfo == nil || shareInfo.ViewNum < 1 {
-		return utils.HTTPErrorHandler(c, errors.New("分享不存在"))
+		return utils.HTTPErrorHandler(c, ErrShareNotFound)
 	}
 
 	if shareInfo.Type == models.ShareTypeFile {
@@ -168,10 +167,10 @@ func GetShareInfo(c *echo.Context) error {
 			return utils.HTTPErrorHandler(c, err)
 		}
 		if fileInfo == nil {
-			return utils.HTTPErrorHandler(c, errors.New("分享文件不存在"))
+			return utils.HTTPErrorHandler(c, ErrShareFileNotFound)
 		}
 		if fileInfo.FileType != models.FileTypeUpload {
-			return utils.HTTPErrorHandler(c, errors.New("分享文件状态错误"))
+			return utils.HTTPErrorHandler(c, ErrInvalidShareFileState)
 		}
 		return utils.HTTPSuccessHandler(c, map[string]any{
 			"id":            shareId,
@@ -200,14 +199,14 @@ func GetShareInfo(c *echo.Context) error {
 func GetShareByPickupCode(c *echo.Context) error {
 	pickupCode := c.Param("code")
 	if pickupCode == "" {
-		return utils.HTTPErrorHandler(c, errors.New("缺少提取码"))
+		return utils.HTTPErrorHandler(c, ErrInvalidRequest)
 	}
 	shareId, err := models.GetRedisPickupData(strings.ToUpper(pickupCode))
 	if err != nil {
 		return utils.HTTPErrorHandler(c, err)
 	}
 	if shareId == "" {
-		return utils.HTTPErrorHandler(c, errors.New("分享不存在"))
+		return utils.HTTPErrorHandler(c, ErrShareNotFound)
 	}
 	return utils.HTTPSuccessHandler(c, map[string]any{
 		"share_id": shareId,
diff --git a/backend/internal/controllers/task.go b/backend/internal/controllers/task.go
index f8f8f7a..4c3b17c 100644
--- a/backend/internal/controllers/task.go
+++ b/backend/internal/controllers/task.go
@@ -3,7 +3,6 @@ package controllers
 import (
 	"backend/internal/controllers/task"
 	"backend/internal/utils"
-	"errors"
 	"pkg/models"
 	u "pkg/utils"
 
@@ -19,11 +18,11 @@ var handleTaskMap = map[string]func(c *echo.Context) ([]byte, error){
 func CreateTask(c *echo.Context) error {
 	taskType := c.Param("type")
 	if taskType == "" {
-		return utils.HTTPErrorHandler(c, errors.New("调用接口参数错误"))
+		return utils.HTTPErrorHandler(c, ErrInvalidRequest)
 	}
 	handleTask, ok := handleTaskMap[taskType]
 	if !ok {
-		return utils.HTTPErrorHandler(c, errors.New("任务不存在"))
+		return utils.HTTPErrorHandler(c, ErrTaskNotFound)
 	}
 	json, err := handleTask(c)
 	if err != nil {
@@ -44,7 +43,7 @@ func CreateTask(c *echo.Context) error {
 func GetTask(c *echo.Context) error {
 	taskId := c.Param("id")
 	if taskId == "" {
-		return utils.HTTPErrorHandler(c, errors.New("调用接口参数错误"))
+		return utils.HTTPErrorHandler(c, ErrInvalidRequest)
 	}
 
 	taskInfo, err := models.GetRedisTaskInfo(taskId)
@@ -56,7 +55,7 @@ func GetTask(c *echo.Context) error {
 
 		queneTaskInfo, err := client.GetTaskInfo("default", taskId)
 		if err != nil {
-			return utils.HTTPErrorHandler(c, errors.New("任务已过期"))
+			return utils.HTTPErrorHandler(c, ErrTaskExpired)
 		}
 		stateMap := map[asynq.TaskState]string{
 			asynq.TaskStateActive:    "processing",
diff --git a/backend/internal/controllers/task/errors.go b/backend/internal/controllers/task/errors.go
new file mode 100644
index 0000000..759459f
--- /dev/null
+++ b/backend/internal/controllers/task/errors.go
@@ -0,0 +1,7 @@
+package task
+
+import "errors"
+
+var (
+	ErrInvalidRequest = errors.New("InvalidRequest")
+)
diff --git a/backend/internal/controllers/task/image.go b/backend/internal/controllers/task/image.go
index 257baae..bee32f6 100644
--- a/backend/internal/controllers/task/image.go
+++ b/backend/internal/controllers/task/image.go
@@ -2,7 +2,6 @@ package task
 
 import (
 	"encoding/json"
-	"errors"
 
 	"github.com/labstack/echo/v5"
 )
@@ -17,7 +16,7 @@ func HandleImageCompress(c *echo.Context) ([]byte, error) {
 		return nil, err
 	}
 	if r.FileId == "" {
-		return nil, errors.New("调用接口参数错误")
+		return nil, ErrInvalidRequest
 	}
 	json, err := json.Marshal(map[string]any{
 		"file_id": r.FileId,
@@ -39,11 +38,12 @@ func HandleImageConvert(c *echo.Context) ([]byte, error) {
 	if err := c.Bind(r); err != nil {
 		return nil, err
 	}
-	if r.FileId == "" {
-		return nil, errors.New("调用接口参数错误")
+	if r.FileId == "" || r.TargetExt == "" {
+		return nil, ErrInvalidRequest
 	}
 	json, err := json.Marshal(map[string]any{
-		"file_id": r.FileId,
+		"file_id":    r.FileId,
+		"target_ext": r.TargetExt,
 	})
 	if err != nil {
 		return nil, err