Abstract: A new method of synthetic research on reliability and performance of control systems by means of automatic control theory is provided in this paper. At first, according to the special feature of control systems, the reliability models of control systems are built, then, a position control system is taken as an example, when the dy-namicparameters are changed, the effect on the systematic reliability is calculated and analysed. Results show that the dynamic parameters not only influence the system dynamics, but also the reliability. In order to design a control system with better performance and reliability, a suitable controller must be carefully designed.