diff --git a/source/module_hamilt_pw/hamilt_pwdft/parallel_grid.cpp b/source/module_hamilt_pw/hamilt_pwdft/parallel_grid.cpp
index 829029e4bb..5d6fe41764 100644
--- a/source/module_hamilt_pw/hamilt_pwdft/parallel_grid.cpp
+++ b/source/module_hamilt_pw/hamilt_pwdft/parallel_grid.cpp
@@ -355,7 +355,6 @@ void Parallel_Grid::reduce(double* rhotot, const double* const rhoin)const
 	// send the Barrier command.
 	if(GlobalV::MY_POOL!=0) 
 	{
-		MPI_Barrier(MPI_COMM_WORLD);
 		return;
 	}
 
@@ -407,8 +406,6 @@ void Parallel_Grid::reduce(double* rhotot, const double* const rhoin)const
 
 	delete[] zpiece;	
 
-	MPI_Barrier(MPI_COMM_WORLD);
-
 	return;
 }
 #endif
diff --git a/source/module_io/write_cube.cpp b/source/module_io/write_cube.cpp
index 8fa212c60f..dbb4e469cf 100644
--- a/source/module_io/write_cube.cpp
+++ b/source/module_io/write_cube.cpp
@@ -35,7 +35,7 @@ void ModuleIO::write_vdata_palgrid(
     // reduce
     std::vector<double> data_xyz_full(nxyz);    // data to be written
 #ifdef __MPI    // reduce to rank 0
-    if (my_pool == 0)
+    if (my_pool == 0 && GlobalV::MY_STOGROUP == 0)
     {
         pgrid.reduce(data_xyz_full.data(), data);
     }
diff --git a/tests/integrate/107_PW_OK/INPUT b/tests/integrate/107_PW_OK/INPUT
index 05c3e66e66..764bb78d76 100644
--- a/tests/integrate/107_PW_OK/INPUT
+++ b/tests/integrate/107_PW_OK/INPUT
@@ -11,6 +11,7 @@ pseudo_dir	../../PP_ORB
 ecutwfc			20
 scf_thr			1e-8
 scf_nmax		100
+kpar           2
 
 out_chg         1
 dft_functional  scan