Abstract: A missile longitudinal overload control is designed based on linear quadratic optimal control method. First of all, a generalized missile threeloop control structure is put forward by using both output feedback law and state reconstruction. Then, an improved fractional controller structure is further derived, on which different fractional order control strategies are analyzed to observe missile dynamic responses. Finally, parameters of the missile fractional order controller are tuned by an improved particle swarm optimization (PSO) algorithm. In order to speed up PSO convergence, both the performance in time domain and frequency domain stability performance and penalty function are combined to construct evaluation function. Simulation results show that the fractional order controller with optimum structure has good control effects.