In distributed island mode, each distributed power source operates in parallel. Because of the difference in impedance values of transmission lines, it is difficult to achieve a reasonable distribution of reactive power output in proportion to the DG capacity using traditional droop control. To solve this problem, this paper proposes an improved self-regulating droop control strategy. Based on the traditional reactive-voltage droop control, the improved strategy introduces a proportional-integral control link on the output reactive power. Then, the reactive power output is independent of line impedance. In this way, the reactive power output can be reasonably distributed according to the DG capacity ratio, and the reactive circulating current component of the system is suppressed. Finally, the DG parallel operation simulation model is built by Matlab simulation platform to verify the effectiveness of the improved strategy. This work is supported by National Natural Science Foundation of China (No. 51567005) and Science and Technology Project of Guizhou Province (No. [2017]7230).