Abstract: LCL grid-connected converter is widely used in the field of new energy power generation. Aiming at the problem of insufficient damping and resonance on both sides of AC/DC of LCL grid-connected converter in high penetration system of new energy, we propose an optimal control strategy of active damping on both sides of AC/DC. In order to suppress the resonance of LCL filter, the state feedback is used to arbitrarily configure the pole characteristics and equivalent passive damping. Combined with the design of the optimal virtual resistor r, the resonance of the LCL filter is significantly suppressed by adjusting the pole to the optimal damping point without sacrificing its filtering characteristics. In order to improve the control characteristics of DC voltage, a damping control loop is introduced in the voltage outer loop, and the damping mechanism is analyzed. The calculation method of the optimal damping coefficient is derived. When the damping is the optimal damping coefficient, the equivalent order reduction of the model can be realized, which significantly enhances the voltage control characteristics. The stability and control characteristics of AC and DC sides before and after the introduction of bilateral damping are compared and analyzed. The analysis results show that the system with damping has better stability and control characteristics. Finally, the effectiveness of the bilateral active damping optimal control strategy is verified by MATLAB/Simulink simulation.