diff --git a/fs.go b/fs.go
index f33195bc..905be9fb 100644
--- a/fs.go
+++ b/fs.go
@@ -6,25 +6,61 @@ import (
 	"path/filepath"
 )
 
-type IFileSystem interface {
-	http.FileSystem
-	Walk(string, filepath.WalkFunc) error
-}
-
-// A File is returned by a FileSystem's Open method and can be
-// served by the FileServer implementation.
-//
-// The methods should behave the same as those on an *os.File.
-type File struct {
-	*os.File
-}
-
 type FileSystem struct {
 }
 
 func (d FileSystem) Open(name string) (http.File, error) {
 	return os.Open(name)
 }
-func (d FileSystem) Walk(root string, walkFn filepath.WalkFunc) error {
-	return filepath.Walk(root, walkFn)
+
+func Walk(fs http.FileSystem, root string, walkFn filepath.WalkFunc) error {
+
+	f, err := fs.Open(root)
+	if err != nil {
+		return err
+	}
+	info, err := f.Stat()
+	if err != nil {
+		err = walkFn(root, nil, err)
+	} else {
+		err = walk(fs, root, info, walkFn)
+	}
+	if err == filepath.SkipDir {
+		return nil
+	}
+	return err
+}
+
+// walk recursively descends path, calling walkFn.
+func walk(fs http.FileSystem, path string, info os.FileInfo, walkFn filepath.WalkFunc) error {
+	var err error
+	if !info.IsDir() {
+		return walkFn(path, info, nil)
+	}
+
+	dir, err := fs.Open(path)
+	defer dir.Close()
+	dirs, err := dir.Readdir(-1)
+	err1 := walkFn(path, info, err)
+	// If err != nil, walk can't walk into this directory.
+	// err1 != nil means walkFn want walk to skip this directory or stop walking.
+	// Therefore, if one of err and err1 isn't nil, walk will return.
+	if err != nil || err1 != nil {
+		// The caller's behavior is controlled by the return value, which is decided
+		// by walkFn. walkFn may ignore err and return nil.
+		// If walkFn returns SkipDir, it will be handled by the caller.
+		// So walk should return whatever walkFn returns.
+		return err1
+	}
+
+	for _, fileInfo := range dirs {
+		filename := filepath.Join(path, fileInfo.Name())
+		err = walk(fs, filename, fileInfo, walkFn)
+		if err != nil {
+			if !fileInfo.IsDir() || err != filepath.SkipDir {
+				return err
+			}
+		}
+	}
+	return nil
 }
diff --git a/template.go b/template.go
index 3321d13f..f8589445 100644
--- a/template.go
+++ b/template.go
@@ -20,6 +20,7 @@ import (
 	"html/template"
 	"io"
 	"io/ioutil"
+	"net/http"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -201,7 +202,7 @@ func BuildTemplate(dir string, files ...string) error {
 		root:  dir,
 		files: make(map[string][]string),
 	}
-	err = fs.Walk(dir, func(path string, f os.FileInfo, err error) error {
+	err = Walk(fs, dir, func(path string, f os.FileInfo, err error) error {
 		return self.visit(path, f, err)
 	})
 	if err != nil {
@@ -235,7 +236,7 @@ func BuildTemplate(dir string, files ...string) error {
 	return nil
 }
 
-func getTplDeep(root string, fs IFileSystem, file string, parent string, t *template.Template) (*template.Template, [][]string, error) {
+func getTplDeep(root string, fs http.FileSystem, file string, parent string, t *template.Template) (*template.Template, [][]string, error) {
 	var fileAbsPath string
 	var rParent string
 	var err error
@@ -279,7 +280,7 @@ func getTplDeep(root string, fs IFileSystem, file string, parent string, t *temp
 	return t, allSub, nil
 }
 
-func getTemplate(root string, fs IFileSystem, file string, others ...string) (t *template.Template, err error) {
+func getTemplate(root string, fs http.FileSystem, file string, others ...string) (t *template.Template, err error) {
 	t = template.New(file).Delims(BConfig.WebConfig.TemplateLeft, BConfig.WebConfig.TemplateRight).Funcs(beegoTplFuncMap)
 	var subMods [][]string
 	t, subMods, err = getTplDeep(root, fs, file, "", t)
@@ -294,7 +295,7 @@ func getTemplate(root string, fs IFileSystem, file string, others ...string) (t
 	return
 }
 
-func _getTemplate(t0 *template.Template, root string, fs IFileSystem, subMods [][]string, others ...string) (t *template.Template, err error) {
+func _getTemplate(t0 *template.Template, root string, fs http.FileSystem, subMods [][]string, others ...string) (t *template.Template, err error) {
 	t = t0
 	for _, m := range subMods {
 		if len(m) == 2 {
@@ -347,9 +348,9 @@ func _getTemplate(t0 *template.Template, root string, fs IFileSystem, subMods []
 	return
 }
 
-type templateFSFunc func() IFileSystem
+type templateFSFunc func() http.FileSystem
 
-func defaultFSFunc() IFileSystem {
+func defaultFSFunc() http.FileSystem {
 	return FileSystem{}
 }
 func SetTemplateFSFunc(fnt templateFSFunc) {
diff --git a/template_test.go b/template_test.go
index d42f7663..287faadc 100644
--- a/template_test.go
+++ b/template_test.go
@@ -267,57 +267,6 @@ type TestingFileSystem struct {
 func (d TestingFileSystem) Open(name string) (http.File, error) {
 	return d.assetfs.Open(name)
 }
-func (d TestingFileSystem) Walk(root string, walkFn filepath.WalkFunc) error {
-
-	f, err := d.Open(root)
-	if err != nil {
-		return err
-	}
-	info, err := f.Stat()
-	if err != nil {
-		err = walkFn(root, nil, err)
-	} else {
-		err = d.walk(root, info, walkFn)
-	}
-	if err == filepath.SkipDir {
-		return nil
-	}
-	return err
-}
-
-// walk recursively descends path, calling walkFn.
-func (d TestingFileSystem) walk(path string, info os.FileInfo, walkFn filepath.WalkFunc) error {
-	var err error
-	if !info.IsDir() {
-		return walkFn(path, info, nil)
-	}
-
-	dir, err := d.Open(path)
-	defer dir.Close()
-	dirs, err := dir.Readdir(-1)
-	err1 := walkFn(path, info, err)
-	// If err != nil, walk can't walk into this directory.
-	// err1 != nil means walkFn want walk to skip this directory or stop walking.
-	// Therefore, if one of err and err1 isn't nil, walk will return.
-	if err != nil || err1 != nil {
-		// The caller's behavior is controlled by the return value, which is decided
-		// by walkFn. walkFn may ignore err and return nil.
-		// If walkFn returns SkipDir, it will be handled by the caller.
-		// So walk should return whatever walkFn returns.
-		return err1
-	}
-
-	for _, fileInfo := range dirs {
-		filename := filepath.Join(path, fileInfo.Name())
-		err = d.walk(filename, fileInfo, walkFn)
-		if err != nil {
-			if !fileInfo.IsDir() || err != filepath.SkipDir {
-				return err
-			}
-		}
-	}
-	return nil
-}
 
 var outputBinData = `<!DOCTYPE html>
 <html>
@@ -341,7 +290,7 @@ var outputBinData = `<!DOCTYPE html>
 `
 
 func TestFsBinData(t *testing.T) {
-	SetTemplateFSFunc(func() IFileSystem {
+	SetTemplateFSFunc(func() http.FileSystem {
 		return TestingFileSystem{&assetfs.AssetFS{Asset: testdata.Asset, AssetDir: testdata.AssetDir, AssetInfo: testdata.AssetInfo}}
 	})
 	dir := "views"