diff --git a/mace/core/runtime/cpu/cpu_runtime.cc b/mace/core/runtime/cpu/cpu_runtime.cc
index f9baac6e6cf528e3bf58f779ead99ab8bca18db0..89c5720604eef730eb1a5a5b48310e27d99de136 100644
--- a/mace/core/runtime/cpu/cpu_runtime.cc
+++ b/mace/core/runtime/cpu/cpu_runtime.cc
@@ -223,7 +223,7 @@ MaceStatus CPURuntime::SetOpenMPThreadsAndAffinityPolicy(
       }
       ++cores_to_use;
     }
-    num_threads_hint = cores_to_use;
+    num_threads_hint = std::min(num_threads_hint, cores_to_use);
   } else {
     cores_to_use = num_threads_hint;
   }