diff --git a/python/sglang/test/bench_one_batch_server_internal.py b/python/sglang/test/bench_one_batch_server_internal.py
index 32c13217a..3ab1abcf2 100644
--- a/python/sglang/test/bench_one_batch_server_internal.py
+++ b/python/sglang/test/bench_one_batch_server_internal.py
@@ -827,9 +827,10 @@ def run_benchmark_internal(
 
     # Warmup
     if not bench_args.skip_warmup:
+        batch_size_unique = list(set(bench_args.batch_size))
         print("=" * 8 + " Warmup Begin " + "=" * 8)
-        print(f"Warmup with batch_size={bench_args.batch_size}")
-        for bs in bench_args.batch_size:
+        print(f"Warmup with batch_size={batch_size_unique}")
+        for bs in batch_size_unique:
             run_one_case(
                 base_url,
                 batch_size=bs,