The variable integral gain voltage and current double closed-loop control technique based on a PWM inverter is studied in this paper. To improve the response speed and steady-state accuracy of the system, the voltage and current double closed-loop control model is established at first, and then the fixed integral of double closed-loop control strategy is analyzed based on this model. Because variable integral gain control method can improve the control precision based on the double closed loop, the voltage and current double closed-loop control strategy with variable integral gain is proposed. Finally, a series of simulation and experiment results are accomplished to verify the validity of this method. It is shown that the dynamic response time is 2ms and the maximum voltage change rate is only at 0.5%, and the steady-state accuracy can reach 99.55%.