Anti jamming performance is an important technical index of the radar, and the fidelity of the jamming environment directly affects the operational efficiency evaluation of radar. According to the demand of modern radar antijamming test, a simulation test system of radar antijamming based on DRFM is designed, and the system function is described. At the same time, target echo, deception jamming, passive clutter and masking jamming mathematical models are constructed; each kind of jamming signal realization method based on DRFM is given. The results of simulation and test show that the radar antijamming simulation test system design scheme presented in this paper can meet the needs of all kinds of required jamming signals and the requirement for testing various radar systems, which provides method for the inspection of radar antijamming performance under the complex environment.