diff --git a/supernode/daemon/mgr/cdn/downloader.go b/supernode/daemon/mgr/cdn/downloader.go
index cf8fde97b..076f06b37 100644
--- a/supernode/daemon/mgr/cdn/downloader.go
+++ b/supernode/daemon/mgr/cdn/downloader.go
@@ -26,6 +26,7 @@ import (
 	errorType "github.com/dragonflyoss/Dragonfly/pkg/errortypes"
 	"github.com/dragonflyoss/Dragonfly/pkg/httputils"
 	"github.com/dragonflyoss/Dragonfly/pkg/rangeutils"
+	"github.com/dragonflyoss/Dragonfly/supernode/httpclient"
 )
 
 // download downloads the file from the original address and
@@ -43,20 +44,29 @@ func (cm *Manager) download(ctx context.Context, taskID, url string, headers map
 			return nil, errors.Wrapf(errorType.ErrInvalidValue, "failed to calculate the breakRange: %v", err)
 		}
 
-		if headers == nil {
-			headers = make(map[string]string)
-		}
 		// check if Range in header? if Range already in Header, use this range directly
-		if _, ok := headers["Range"]; !ok {
-			headers["Range"] = httputils.ConstructRangeStr(breakRange)
+		if !hasRange(headers) {
+			headers = httpclient.CopyHeader(
+				map[string]string{"Range": httputils.ConstructRangeStr(breakRange)},
+				headers)
+
 		}
 		checkCode = []int{http.StatusPartialContent}
 	}
 
-	logrus.Infof("start to download for taskId(%s) with fileUrl: %s header: %v checkCode: %d", taskID, url, headers, checkCode)
+	logrus.Infof("start to download for taskId(%s) with fileUrl: %s"+
+		" header: %v checkCode: %d", taskID, url, headers, checkCode)
 	return cm.originClient.Download(url, headers, checkStatusCode(checkCode))
 }
 
+func hasRange(headers map[string]string) bool {
+	if headers == nil {
+		return false
+	}
+	_, ok := headers["Range"]
+	return ok
+}
+
 func checkStatusCode(statusCode []int) func(int) bool {
 	return func(status int) bool {
 		for _, s := range statusCode {
diff --git a/supernode/daemon/mgr/cdn/downloader_test.go b/supernode/daemon/mgr/cdn/downloader_test.go
index 36deb814d..f9101de87 100644
--- a/supernode/daemon/mgr/cdn/downloader_test.go
+++ b/supernode/daemon/mgr/cdn/downloader_test.go
@@ -105,7 +105,9 @@ func (s *CDNDownloadTestSuite) TestDownload(c *check.C) {
 	}
 
 	for _, v := range cases {
+		headers := cloneMap(v.headers)
 		resp, err := cm.download(context.TODO(), "", ts.URL, v.headers, v.startPieceNum, v.httpFileLength, v.pieceContSize)
+		c.Check(headers, check.DeepEquals, v.headers)
 		c.Check(v.errCheck(err), check.Equals, true)
 
 		c.Check(resp.StatusCode, check.Equals, v.exceptedStatusCode)
@@ -160,3 +162,17 @@ func Test_checkStatusCode(t *testing.T) {
 		})
 	}
 }
+
+// ----------------------------------------------------------------------------
+// helper
+
+func cloneMap(src map[string]string) map[string]string {
+	if src == nil {
+		return nil
+	}
+	target := make(map[string]string)
+	for k, v := range src {
+		target[k] = v
+	}
+	return target
+}
diff --git a/supernode/httpclient/origin_http_client.go b/supernode/httpclient/origin_http_client.go
index 2b3fc1600..5f6ee4a11 100644
--- a/supernode/httpclient/origin_http_client.go
+++ b/supernode/httpclient/origin_http_client.go
@@ -132,18 +132,16 @@ func (client *OriginClient) GetContentLength(url string, headers map[string]stri
 
 // IsSupportRange checks if the source url support partial requests.
 func (client *OriginClient) IsSupportRange(url string, headers map[string]string) (bool, error) {
-	// set headers
-	if headers == nil {
-		headers = make(map[string]string)
-	}
-	headers["Range"] = "bytes=0-0"
+	// set headers: headers is a reference to map, should not change it
+	copied := CopyHeader(nil, headers)
+	copied["Range"] = "bytes=0-0"
 
 	// send request
-	resp, err := client.HTTPWithHeaders(http.MethodGet, url, headers, 4*time.Second)
+	resp, err := client.HTTPWithHeaders(http.MethodGet, url, copied, 4*time.Second)
 	if err != nil {
 		return false, err
 	}
-	resp.Body.Close()
+	_ = resp.Body.Close()
 
 	if resp.StatusCode == http.StatusPartialContent {
 		return true, nil
@@ -157,20 +155,18 @@ func (client *OriginClient) IsExpired(url string, headers map[string]string, las
 		return true, nil
 	}
 
-	// set headers
-	if headers == nil {
-		headers = make(map[string]string)
-	}
+	// set headers: headers is a reference to map, should not change it
+	copied := CopyHeader(nil, headers)
 	if lastModified > 0 {
 		lastModifiedStr, _ := netutils.ConvertTimeIntToString(lastModified)
-		headers["If-Modified-Since"] = lastModifiedStr
+		copied["If-Modified-Since"] = lastModifiedStr
 	}
 	if !stringutils.IsEmptyStr(eTag) {
-		headers["If-None-Match"] = eTag
+		copied["If-None-Match"] = eTag
 	}
 
 	// send request
-	resp, err := client.HTTPWithHeaders(http.MethodGet, url, headers, 4*time.Second)
+	resp, err := client.HTTPWithHeaders(http.MethodGet, url, copied, 4*time.Second)
 	if err != nil {
 		return false, err
 	}
@@ -222,3 +218,14 @@ func (client *OriginClient) HTTPWithHeaders(method, url string, headers map[stri
 	}
 	return httpClient.Do(req)
 }
+
+// CopyHeader copies the src to dst and return a non-nil dst map.
+func CopyHeader(dst, src map[string]string) map[string]string {
+	if dst == nil {
+		dst = make(map[string]string)
+	}
+	for k, v := range src {
+		dst[k] = v
+	}
+	return dst
+}
diff --git a/supernode/httpclient/origin_http_client_test.go b/supernode/httpclient/origin_http_client_test.go
index 971f04466..5b066a35f 100644
--- a/supernode/httpclient/origin_http_client_test.go
+++ b/supernode/httpclient/origin_http_client_test.go
@@ -98,3 +98,16 @@ func (s *OriginHTTPClientTestSuite) TestRegisterTLSConfig(c *check.C) {
 	c.Assert(resp, check.NotNil)
 	c.Assert(resp.ContentLength, check.Equals, int64(-1))
 }
+
+func (s *OriginHTTPClientTestSuite) TestCopyHeader(c *check.C) {
+	dst := CopyHeader(nil, nil)
+	c.Check(dst, check.NotNil)
+	c.Check(len(dst), check.Equals, 0)
+
+	src := map[string]string{"test": "1"}
+	dst = CopyHeader(nil, src)
+	c.Check(dst, check.DeepEquals, src)
+
+	dst["test"] = "2"
+	c.Check(src["test"], check.Equals, "1")
+}