diff -Naur rpm/tests/compatible/gpu/nvidia_gpu.py oech/tests/compatible/gpu/nvidia_gpu.py
--- rpm/tests/compatible/gpu/nvidia_gpu.py	2024-06-07 16:37:44.542417257 +0800
+++ oech/tests/compatible/gpu/nvidia_gpu.py	2024-06-07 16:38:57.149472108 +0800
@@ -174,7 +174,7 @@
                 self.logger.error("Using nvidia-smi to test Drvier failed.")
 
             env_display = os.getenv('DISPLAY')
-            if env_display != '':
+            if env_display is not None and env_display != '':
                 self.logger.info("Start to test Vulkan.")
                 self.set_default_gpu()
                 code = self.command.run_cmd(
