Aiming at the problem that it is difficult to keep the three-phase load current stable in complex environment and nonlinear or changeable load, and it is difficult to adjust the controller parameters optimally, a particle swarm optimization (PSO) algorithm is proposed to find the optimal parameters of Quasi-PR controller to stabilize the load current. Firstly, considering DC voltage, inverter circuit structure, filter circuit structure and line impedance, the simulation model is built by Matlab electrical module; secondly, PSO algorithm is used to optimize the proportion and resonance parameters of quasi-PR controller in the model, in which the algorithm improves the inertia parameters and adds the treatment of particle boundary crossing problem; Finally, after setting the load parameters, the controller improved by PSO algorithm is better than the controller obtained from empirical formula in control effect, the total harmonic distortion rate(THD) of current is reduced, and the stability is better.