Aiming at the problem that parameter tuning is too much relying on the experience in control design of multi-rotor unmanned aerial vehicle(UAV) flight, an automatic parameter tuning is proposed based on the corresponding relationship between controller parameters and the performance response of the control system. Firstly, optimization goal and constraints are confirmed by particle swarm optimization (PSO) according to the performance requirements of the controller. Secondly, the nonlinear model of the controlled object is built. The parameter range is estimated by the practical engineering method. And then the controller parameters meeting the performance index are automatically found out based on the rapid optimization characteristic of PSO. Finally, the model is simulated and verified by Matlab/Simulink. Simulation results show that the PSO algorithm can automatically adjust the flight control parameters of multi rotor UAV controller quickly and accurately.