The phase plane is already an important method to design fuzzy control systems and analyze their stability. The concept of the real-time response trajectory characteristic vectors and angles between the real-time characteristic vectors on the phase plane are put forward in this paper according to the analysis of the response trajectory performance on the phase plane of a fuzzy control system. The method of rule self-tuning fuzzy control based on the response trajectory performance on phase plane is presented by analyzing the characteristics of angles between the real-time characteristic vectors. The simulation results show that the method is not only capable of increasing greatly the ability to identify and describe the plant in small error, reducing the overshoot, settle time greatly and improving the convergence speed of the fuzzy control system, but also possesses a simple arithmetic and does not require much more storage space and calculation time.