When the traditional extended Kalman filter (EKF) algorithm is used in integrated navigation system of future aircraft, it may lead to the inaccuracy of the model because of linearization and the decreasing of navigation precision. Particle filter (PF) solves Bayes estimation problem by using Monte Carlo method and can effectively avoid bringing in linearization error. Consequently, aimed at the requirement of high accuracy for the navigation system state parameters in launch inertial coordinate system, it is particularly important to improve the accuracy of filter algorithm for missile borne integrated navigation system. The PF algorithm can directly achieve an error estimation without linearization of nonlinear system. This paper brings PF algorithm into the SINS/GPS/CNS integrated navigation system.PF algorithm is designed based on federal filter and the navigation system state parameters are estimated directly. The algorithm simulation results indicate PF algorithm effectively improves filtering precision compared with EKF algorithm and is very suitable for integrated navigati on system.