In the inverter parallel system, because of the difference of line impedance, the power distribution accuracy of traditional droop control is not high, and the output voltage control accuracy is low in complex working conditions. To solve these problems, an improved droop control method based on adaptive parameters is proposed. Based on traditional P-V droop control, this method is replaced by an adaptive parameter control based on the Lyapunov function. This can reduce the influence of the original line impedance and ensure that the output voltage is kept within a certain constraint range under any load condition. In addition, virtual impedance is added to the control loop, and the proportional coefficient of the virtual impedance is adjusted through active power feedback to further improve the accuracy of power distribution. Simulation and experimental results verify the effectiveness of the proposed improved droop control method.