Aiming at the the nonlinear problem between the control surface deflection angle and the moment coefficient of an aircraft with multiple control surface, an improved particle swarm optimization (PSO) algorithm combined with sequential quadratic programming (SQP) algorithm was proposed to solve the nonlinear control allocation problem. Taking the flying wing model as the object, the rudder effectiveness of the model is analyzed, and in the case of nonlinear rudder effectiveness, the method of fitting function is used to represent the nonlinearity of rudder effectiveness; the particle swarm algorithm is improved, and the sequential quadratic programming method is improved by using quasi-Newton method and line search method; and the fitting effect of the improved algorithm is compared; The effectiveness of the algorithm is verified by simulation comparison between linear and nonlinear rudder effects. The simulation results show that the algorithm can improve the global search ability of the particle swarm algorithm and ensures the accuracy of the allocation.