diff --git a/rust-build/ohos_ci_build.sh b/rust-build/ohos_ci_build.sh
index 79c9eda9f66f7ccbd91fa7873c8e0ec327895b1f..00314c66c8013616f6e51adf52929052ceacdb1f 100644
--- a/rust-build/ohos_ci_build.sh
+++ b/rust-build/ohos_ci_build.sh
@@ -51,7 +51,7 @@ download_rust() {
 get_new_version() {
     pushd ${root_build_dir}/../harmony/llvm/
     local commit_id_full=$(git rev-parse HEAD)
-    local commit_id_short=$(expr substr "$commit_id_full" 1 10)
+    local commit_id_short=${commit_id_full:1:10}
     new_version="OHOS llvm-preject $commit_id_short"
     popd
 }