Abstract: Nuclear power plant (NPP) is a multi-input & multi-output, no-linear and time-varying complex system. The conventional PID controller is usually used in NPP control system which is based on analog instrument. The system parameters are easy to overshoot and the response time is longer in the control mode of the conventional PID. In order to improve this condition, a new coordinated control strategy which is based on expert system and the original controllers in the digital instrument & control technology was presented. In order to verify and validate it, the proposed coordinated control technology was tested by the full-scope real-time simulation system. The results prove that using digital instrument & control technology to achieve coordinated controller is feasible, the coordinated controller can effectively improve the dynamic operating characteristics of the system, and the coordinated controller is superior to the conventional PID controller in control performance.