diff --git a/update_mirror.sh b/update_mirror.sh
index 91b99c2142abe5a57fb2129e27ea3a5901e6514d..b6884bb1999143a7828b2c64353fd1ba316526f3 100755
--- a/update_mirror.sh
+++ b/update_mirror.sh
@@ -39,7 +39,9 @@ if git config --get svn-remote.svn.url &> /dev/null;then
   git for-each-ref --format="%(objectname:short) %(refname)" refs/remotes/tags |  while read ref; do
     objectname=$(echo $ref | cut -d " " -f 1)
     tagname=$(echo $ref | cut -d " " -f 2 | cut -d / -f 4)
-    GIT_COMMITTER_DATE="$(git show --format=%aD  | head -1)" git tag -a $tagname -m "import '$tagname' tag from svn" $objectname
+    if [ ! git show-ref --tags | egrep -q "refs/tags/$tagname$"]; then
+      GIT_COMMITTER_DATE="$(git show --format=%aD  | head -1)" git tag -a $tagname -m "import '$tagname' tag from svn" $objectname
+    fi
   done
 
   cd .git