diff --git a/src/allreduce_base.h b/src/allreduce_base.h
index c34eb6042..92aa849c8 100644
--- a/src/allreduce_base.h
+++ b/src/allreduce_base.h
@@ -90,6 +90,7 @@ class AllreduceBase : public IEngine {
                          PreprocFunction prepare_fun = NULL,
                          void *prepare_arg = NULL) {
     if (prepare_fun != NULL) prepare_fun(prepare_arg);
+    if (world_size == 1) return;
     utils::Assert(TryAllreduce(sendrecvbuf_,
                                type_nbytes, count, reducer) == kSuccess,
                   "Allreduce failed");
@@ -101,6 +102,7 @@ class AllreduceBase : public IEngine {
    * \param root the root worker id to broadcast the data
    */
   virtual void Broadcast(void *sendrecvbuf_, size_t total_size, int root) {
+    if (world_size == 1) return;
     utils::Assert(TryBroadcast(sendrecvbuf_, total_size, root) == kSuccess,
                   "Broadcast failed");
   }