diff --git a/pkg/filesystem/driver/s3/handler.go b/pkg/filesystem/driver/s3/handler.go
index 819058d..56a7aaa 100644
--- a/pkg/filesystem/driver/s3/handler.go
+++ b/pkg/filesystem/driver/s3/handler.go
@@ -326,9 +326,10 @@ func (handler *Driver) Token(ctx context.Context, ttl int64, uploadSession *seri
 	// 创建分片上传
 	expires := time.Now().Add(time.Duration(ttl) * time.Second)
 	res, err := handler.svc.CreateMultipartUpload(&s3.CreateMultipartUploadInput{
-		Bucket:  &handler.Policy.BucketName,
-		Key:     &fileInfo.SavePath,
-		Expires: &expires,
+		Bucket:      &handler.Policy.BucketName,
+		Key:         &fileInfo.SavePath,
+		Expires:     &expires,
+		ContentType: aws.String(fileInfo.DetectMimeType()),
 	})
 	if err != nil {
 		return nil, fmt.Errorf("failed to create multipart upload: %w", err)
diff --git a/pkg/filesystem/fsctx/stream.go b/pkg/filesystem/fsctx/stream.go
index 4cf48e3..512270b 100644
--- a/pkg/filesystem/fsctx/stream.go
+++ b/pkg/filesystem/fsctx/stream.go
@@ -2,6 +2,7 @@ package fsctx
 
 import (
 	"errors"
+	"github.com/HFO4/aliyun-oss-go-sdk/oss"
 	"io"
 	"time"
 )
@@ -17,7 +18,7 @@ const (
 
 type UploadTaskInfo struct {
 	Size            uint64
-	MIMEType        string
+	MimeType        string
 	FileName        string
 	VirtualPath     string
 	Mode            WriteMode
@@ -30,6 +31,15 @@ type UploadTaskInfo struct {
 	Src             string
 }
 
+// Get mimetype of uploaded file, if it's not defined, detect it from file name
+func (u *UploadTaskInfo) DetectMimeType() string {
+	if u.MimeType != "" {
+		return u.MimeType
+	}
+
+	return oss.TypeByExtension(u.FileName)
+}
+
 // FileHeader 上传来的文件数据处理器
 type FileHeader interface {
 	io.Reader
@@ -51,7 +61,7 @@ type FileStream struct {
 	Size            uint64
 	VirtualPath     string
 	Name            string
-	MIMEType        string
+	MimeType        string
 	SavePath        string
 	UploadSessionID *string
 	AppendStart     uint64
@@ -90,7 +100,7 @@ func (file *FileStream) Seekable() bool {
 func (file *FileStream) Info() *UploadTaskInfo {
 	return &UploadTaskInfo{
 		Size:            file.Size,
-		MIMEType:        file.MIMEType,
+		MimeType:        file.MimeType,
 		FileName:        file.Name,
 		VirtualPath:     file.VirtualPath,
 		Mode:            file.Mode,
diff --git a/pkg/webdav/webdav.go b/pkg/webdav/webdav.go
index 054bced..9b2ff1b 100644
--- a/pkg/webdav/webdav.go
+++ b/pkg/webdav/webdav.go
@@ -345,7 +345,7 @@ func (h *Handler) handlePut(w http.ResponseWriter, r *http.Request, fs *filesyst
 	fileName := path.Base(reqPath)
 	filePath := path.Dir(reqPath)
 	fileData := fsctx.FileStream{
-		MIMEType:    r.Header.Get("Content-Type"),
+		MimeType:    r.Header.Get("Content-Type"),
 		File:        r.Body,
 		Size:        fileSize,
 		Name:        fileName,
diff --git a/service/explorer/file.go b/service/explorer/file.go
index 287a582..0fa1b8e 100644
--- a/service/explorer/file.go
+++ b/service/explorer/file.go
@@ -408,7 +408,7 @@ func (service *FileIDService) PutContent(ctx context.Context, c *gin.Context) se
 	}
 
 	fileData := fsctx.FileStream{
-		MIMEType: c.Request.Header.Get("Content-Type"),
+		MimeType: c.Request.Header.Get("Content-Type"),
 		File:     c.Request.Body,
 		Size:     fileSize,
 		Mode:     fsctx.Overwrite,
diff --git a/service/explorer/upload.go b/service/explorer/upload.go
index d14f328..0c26c26 100644
--- a/service/explorer/upload.go
+++ b/service/explorer/upload.go
@@ -26,6 +26,7 @@ type CreateUploadSessionService struct {
 	Name         string `json:"name" binding:"required"`
 	PolicyID     string `json:"policy_id" binding:"required"`
 	LastModified int64  `json:"last_modified"`
+	MimeType     string `json:"mime_type"`
 }
 
 // Create 创建新的上传会话
@@ -51,6 +52,7 @@ func (service *CreateUploadSessionService) Create(ctx context.Context, c *gin.Co
 		Name:        service.Name,
 		VirtualPath: service.Path,
 		File:        ioutil.NopCloser(strings.NewReader("")),
+		MimeType:    service.MimeType,
 	}
 	if service.LastModified > 0 {
 		lastModified := time.UnixMilli(service.LastModified)
@@ -174,7 +176,7 @@ func processChunkUpload(ctx context.Context, c *gin.Context, fs *filesystem.File
 	}
 
 	fileData := fsctx.FileStream{
-		MIMEType:     c.Request.Header.Get("Content-Type"),
+		MimeType:     c.Request.Header.Get("Content-Type"),
 		File:         c.Request.Body,
 		Size:         fileSize,
 		Name:         session.Name,