Abstract: As the PLL may decrease the stability of the grid-connected inverter under weak grid,a phase-locked loop bandwidth adaptive control strategy is proposed to realize the obtaining of the optimal control parameters by the phase-locked loop parameters based on the real-time impedance value of the grid,to ensure the optimal control performance of the system and the stable operation,so as to enhance the adaptive ability of the grid-following type of inverters to the impedance of the grid under weak grid. PSCAD/EMTDC is utilized for the simulation verification,and the simulation results prove that the adaptive control strategy proposed in the paper is correct and effective.