diff --git a/bioflow_service/app/services/bioflow/extension_exec.py b/bioflow_service/app/services/bioflow/extension_exec.py
index bf3f6c9..460250c 100644
--- a/bioflow_service/app/services/bioflow/extension_exec.py
+++ b/bioflow_service/app/services/bioflow/extension_exec.py
@@ -111,7 +111,10 @@ class ExtensionExecutor:
         cmd += ["-v", f"{self.cfg.entry_script_dir}:{self.cfg.container_entry_dir}:ro"]
         cmd += ["--cpus", self._safe_cpu(request.cpu or self.cfg.default_cpus)]
         cmd += ["--memory", self._safe_memory(request.memory or self.cfg.default_memory)]
-        cmd.append(f"{request.image}:{self.cfg.docker_tag_suffix}")
+        # 镜像名可能已含 tag(自动生成的 bioflow-ext-<fp>:<suffix>);
+        # 未含 tag 时才补 suffix——否则拼成 a:b:b 的非法引用(真实 bug)。
+        image_ref = str(request.image)
+        cmd.append(image_ref if ":" in image_ref else f"{image_ref}:{self.cfg.docker_tag_suffix}")
         cmd += ["python", "-B", CONTAINER_ENTRY]
         cmd += ["--ext-dir", self.cfg.container_ext_dir]
         cmd += ["--input-dir", self.cfg.container_input_dir]