diff --git a/pkg/storage/gcs.go b/pkg/storage/gcs.go
index 8e82b228f..956a5f488 100644
--- a/pkg/storage/gcs.go
+++ b/pkg/storage/gcs.go
@@ -135,7 +135,7 @@ func (s *gcsStorage) Open(ctx context.Context, path string) (ReadSeekCloser, err
 // The first argument is the file path that can be used in `Open`
 // function; the second argument is the size in byte of the file determined
 // by path.
-func (s *gcsStorage) WalkDir(ctx context.Context, dir string, listCount int64, fn func(string, int64) error) error {
+func (s *gcsStorage) WalkDir(ctx context.Context, opt *WalkOption, fn func(string, int64) error) error {
 	// TODO, implement this if needed
 	panic("Unsupported Operation")
 }
diff --git a/pkg/storage/local.go b/pkg/storage/local.go
index 2bca89c09..25678d7cd 100644
--- a/pkg/storage/local.go
+++ b/pkg/storage/local.go
@@ -41,7 +41,7 @@ func (l *LocalStorage) FileExists(ctx context.Context, name string) (bool, error
 // The first argument is the file path that can be used in `Open`
 // function; the second argument is the size in byte of the file determined
 // by path.
-func (l *LocalStorage) WalkDir(ctx context.Context, dir string, listCount int64, fn func(string, int64) error) error {
+func (l *LocalStorage) WalkDir(ctx context.Context, opt *WalkOption, fn func(string, int64) error) error {
 	return filepath.Walk(l.base, func(path string, f os.FileInfo, err error) error {
 		if err != nil {
 			return errors.Trace(err)
diff --git a/pkg/storage/noop.go b/pkg/storage/noop.go
index ecee13115..a29d62e1d 100644
--- a/pkg/storage/noop.go
+++ b/pkg/storage/noop.go
@@ -29,7 +29,7 @@ func (*noopStorage) Open(ctx context.Context, path string) (ReadSeekCloser, erro
 }
 
 // WalkDir traverse all the files in a dir.
-func (*noopStorage) WalkDir(ctx context.Context, dir string, listCount int64, fn func(string, int64) error) error {
+func (*noopStorage) WalkDir(ctx context.Context, opt *WalkOption, fn func(string, int64) error) error {
 	return nil
 }
 
diff --git a/pkg/storage/s3.go b/pkg/storage/s3.go
index 94b63d3c4..c9423a7c1 100644
--- a/pkg/storage/s3.go
+++ b/pkg/storage/s3.go
@@ -9,6 +9,7 @@ import (
 	"io"
 	"io/ioutil"
 	"net/url"
+	"strings"
 
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/aws/awserr"
@@ -363,13 +364,14 @@ func (rs *S3Storage) FileExists(ctx context.Context, file string) (bool, error)
 // The first argument is the file path that can be used in `Open`
 // function; the second argument is the size in byte of the file determined
 // by path.
-func (rs *S3Storage) WalkDir(ctx context.Context, dir string, listCount int64, fn func(string, int64) error) error {
+func (rs *S3Storage) WalkDir(ctx context.Context, opt *WalkOption, fn func(string, int64) error) error {
 	var marker *string
-	prefix := rs.options.Prefix + dir
+	prefix := rs.options.Prefix + opt.SubDir
 	maxKeys := int64(1000)
-	if listCount > 0 {
-		maxKeys = listCount
+	if opt.ListCount > 0 {
+		maxKeys = opt.ListCount
 	}
+
 	req := &s3.ListObjectsInput{
 		Bucket:  aws.String(rs.options.Bucket),
 		Prefix:  aws.String(prefix),
@@ -382,7 +384,11 @@ func (rs *S3Storage) WalkDir(ctx context.Context, dir string, listCount int64, f
 			return err
 		}
 		for _, r := range res.Contents {
-			if err = fn(*r.Key, *r.Size); err != nil {
+			// when walk on specify directory, the result include storage.Prefix,
+			// which can not be reuse in other API(Open/Read) directly.
+			// so we use TrimPrefix to filter Prefix for next Open/Read.
+			path := strings.TrimPrefix(*r.Key, rs.options.Prefix)
+			if err = fn(path, *r.Size); err != nil {
 				return err
 			}
 		}
diff --git a/pkg/storage/storage.go b/pkg/storage/storage.go
index a8fd0f3fe..ff1a1eeee 100644
--- a/pkg/storage/storage.go
+++ b/pkg/storage/storage.go
@@ -10,6 +10,14 @@ import (
 	"github.com/pingcap/kvproto/pkg/backup"
 )
 
+// WalkOption is the option of storage.WalkDir.
+type WalkOption struct {
+	// walk on SubDir of specify directory
+	SubDir string
+	// number of list count, default 1000
+	ListCount int64
+}
+
 // ReadSeekCloser is the interface that groups the basic Read, Seek and Close methods.
 type ReadSeekCloser interface {
 	io.Reader
@@ -41,7 +49,7 @@ type ExternalStorage interface {
 	// The argument `path` is the file path that can be used in `Open`
 	// function; the argument `size` is the size in byte of the file determined
 	// by path.
-	WalkDir(ctx context.Context, dir string, listCount int64, fn func(path string, size int64) error) error
+	WalkDir(ctx context.Context, opt *WalkOption, fn func(path string, size int64) error) error
 
 	// CreateUploader create a uploader that will upload chunks data to storage.
 	// It's design for s3 multi-part upload currently. e.g. cdc log backup use this to do multi part upload