diff --git a/mace/ops/bias_add_test.cc b/mace/ops/bias_add_test.cc
index 507cd05d3c315781e9e2b8fdfca409811b7a1426..8cab655b1472f3056ce1bf65c015ee50525fb26a 100644
--- a/mace/ops/bias_add_test.cc
+++ b/mace/ops/bias_add_test.cc
@@ -64,8 +64,8 @@ TEST_F(BiasAddOpTest, SimpleRandomOPENCL) {
   // generate random input
   index_t batch = 1 + rand() % 10;
   index_t channels = 3 + rand() % 50;
-  index_t height = 64;
-  index_t width = 64;
+  index_t height = 64 + rand() % 50;
+  index_t width = 64 + rand() % 50;
 
   // Construct graph
   auto &net = test_net();
@@ -110,8 +110,8 @@ TEST_F(BiasAddOpTest, ComplexRandomOPENCL) {
   // generate random input
   index_t batch = 1 + rand() % 10;
   index_t channels = 3 + rand() % 50;
-  index_t height = 103;
-  index_t width = 113;
+  index_t height = 103 + rand() % 100;
+  index_t width = 113 + rand() % 100;
 
   // Construct graph
   auto &net = test_net();