Surface source infrared decoy is regarded as the new type weapon to confront infrared guided missile. In comparison with traditional infrared decoy, it has obvious superiority in burning rate, diffusion range, jamming effectiveness and so on. It′s of great significance to study the anti-interference mechanism of infrared guided missile for improving the jamming effectiveness. Firstly, the models of missile motion, seeker tracking and the optimization algorithm of tracking were introduced. Secondly, the models of flight motion and radiation were established, as well as models of surface source infrared decoy diffusion and infrared image. Finally, the tactical parameters of missile was selected and the indicator of effectiveness evaluation was formulated, based on which, comparing the simulation results with testing data to verify the reasonability of simulation result. It′s concluded from simulation that the simulation results of the influence of tactical parameters of missile on jamming effectiveness of surface source infrared decoy match the testing data, being of great reference value.