Abstract: Because of the frequency and voltage of the micro-grid will fluctuate greatly, when the sudden load change in the islanding operation mode and transfer between grid-connected and islanding operation, which reduces the stability of the micro-grid operation. In order to solve the above problems and improve the power quality of the micro-grid, the micro-grid control strategy is optimized, based on the droop control. Added frequency correction function of the adjustable PID parameter in the P-f control section to improve the frequency characteristics of the micro-grid. The fuzzy adaptive PID controller is added in the Q-U control section to reduce the fluctuation of the micro-grid voltage. A phase synchronization with voltage adjustment module is designed, to achieve the smooth and fast transfer between grid-connected and islanding operation. Finally, a simulation model is set up in Simulink, the above improvements and designs are simulated. The simulation verifies that the optimized control strategy makes the micro-grid operation more stable.