The capacitor current feedback active damping control method is often used in a three-phase LCL grid-connected inverter. However, because of the existence of control delay, the active damping characteristics of the system change at 1/6fs, and system instability may occur in a weak grid. A leading delay compensation method based on improved capacitor current feedback is proposed to solve this problem. Based on the stability design requirements of passive theory, and through a stability analysis of the control inner loop, the control parameters of the inner loop and the feasible region of improved capacitor current feedback coefficient are given. Through the stability analysis of the control outer loop, the feasible region of the control parameters of the outer loop is given. A parameter analysis and design process from inner loop to outer loop is adopted to expand the effective positive damping region to nearly 0.45fs, which effectively ensures the passivity of the output admittance of the inverter. Discrete stability analysis and simulation results show that the proposed method has better system stability, robustness, and dynamic response characteristic than the traditional capacitive current feedback method under increased grid impedance, parallel coupling of inverters, and fluctuation of filter parameters. This work is supported by the National Key Research and Development Program of China (No. 2021YFB2400900).