diff --git a/vllm_omni/entrypoints/cli/serve.py b/vllm_omni/entrypoints/cli/serve.py
index acefc081b..ac03de143 100644
--- a/vllm_omni/entrypoints/cli/serve.py
+++ b/vllm_omni/entrypoints/cli/serve.py
@@ -245,7 +245,7 @@ class OmniServeCommand(CLISubcommand):
         # Diffusion model mixed precision
         omni_config_group.add_argument(
             "--max-generated-image-size",
-            type=float,
+            type=int,
             help="The max size of generate image (height * width).",
         )
         return serve_parser