Abstract: A current control method based on auto-coupling PID control theory is proposed to address the issues of slow current tracking speed and large overshoot when the power of three-phase grid connected inverters suddenly changes. This method considers the known or unknown internal dynamics of LCL type three-phase grid connected inverter and the disturbances caused by the grid voltage as total disturbances,and then the nonlinear disturbance system can be equivalent to a linear disturbance system. Furthermore,a controlled error system under the inverse excitation of total disturbance is constructed. An auto-coupling PI current controller based on speed factor is designed accordingly. Theoretical analysis shows that the auto-coupling PI closed-loop control system has good robust stability and disturbance resistance robustness. Simulation experiments have shown that this method has dynamic qualities such as fast response speed,high control accuracy and strong anti-interference ability. The response time is about 2 ms,and the proposed method has good practical application prospects in the field of distributed power grid connection.