Aiming at the test problems caused by the limited cycle of existing automatic processing equipment, this paper takes the chamfering device as the research object, and develops a small PLC half-physical simulation system by using virtual reality technology. The system includes PLC, virtual communication module and virtual 3D model. Mitsubishi FX5U series PLC for the host computer, use programming to control the 3D model. Virtual communication module transmits data by serial communication. The virtual 3D model acts as the lower machine and drives the motion of the model through the received data. The simulation results show that the system can verify the correctness of PLC program and provide a new test method for automatic equipment production line.