Abstract: In order to evaluate the comprehensive performance of the control system accurately and comprehensively, an improved comprehensive performance evaluation system of TOPSIS control system based on Mahalanobis distance is established, and the weight of multi-attribute evaluation indicators is determined by game theory. Since the superheated steam temperature has dynamic characteristics such as large inertia and nonlinearity, we selected multiple evaluation indicators according to the requirements of quality control, including overshoot, adjustment time and disturbance recovery time etc., and studied three aspects of controlling system in stability, rapid response performance and anti-interference. We then obtained the relative closeness of the control plan to be evaluated under the Mahalanobis distance and finally screened out the optimal control plan. We carried out the simulation verification of the traditional PID and fuzzy PID control systems and the results show that the method is effective for the comprehensive evaluation of system control performance and can better maintain the comprehensive performance of the control systems of the thermal power unit.