Abstract: For dynamic analysis of outboard active decoy jamming on the terminal radar guidance, the angular deviation under active decoy jamming is derived based on the measuring principle of monopulse radar, and the jamming difference between sum-difference method of amplitude and the phase method is compared. Combined with the signal and the macro situation, the calculation methods of the critical jamming distance of missile and the critical lateral distance of decoy to achieve effective jamming are analyzed and proposed as the quantitative basis of decoy jamming strategy. By developing a simulation platform to simulate the dynamic process of active decoy jamming, the applicability of the theoretical analysis are verified. The results show that the requirement for the active decoy to achieve effective jamming during the terminal process of anti-ship missiles is that the decoy deployment distance should be greater than the critical lateral distance, and maneuvering decoy can improve the robustness of non-cooperative jamming.