For the current deficiencies of internal air to air missile kill probability model against fighter, based on the analysis on the characteristics of aircraft, and methods of Monte Carlo method and kinematics principle are combined to establish kill probability model of warhead fragments and shock wave. Based on the established single kill probability model, objective particle swarm optimization algorithm is used to optimize the loading coefficient, fragments numbers, fragment mass, static scattering angle, static scattering direction angle, the optimization results not only improve the missile kill probability and its main parameters, but also reduce the quality of the warhead.