With the development of science and technology, weapon system is threatened by more and more electronic interference. Computer simulation has the characteristics of safety, efficiency, economy and so on, which has become an important means in the field of radar and electronic countermeasures at present and in the future. The modular design of Simulink is adopted to simulate the signal level of the pulse Doppler radar, and the radar simulation system is established. The user can modify the parameters of the radar through the simulation boundary, so as to simulate the radar performance that the user wants.