Abstract: As one of the key components of Nuclear Power Systems, Reactor Pressure Vessel (RPV) has to be applicable for the environment with high-pressure, high-temperature and strong radiation from neutrons. In order to monitor the RPV′s running conditions, and to avoid the dangerousness to human from touching, a video-inspection system has been designed and complimented, which is mainly based on the programmed logical circuit (PLC) to control RPV finely and perfectly with the considerations from mechanics and electronic connecting. The feedbacks from the engineering application proved the good efficiency of this system.