Aiming at the micro source and Energy storage unit which based on inverter，P/Q control was summarized and the droop control strategy of battery energy storage was detailed analyzed in this paper, and an improved P/V droop control strategy in low voltage system was proposed. It added power differential term to reduce the lag caused by the power calculation part. By adding feed-forward control to give secondary regulation of the voltage and frequency can be achieved, which reduced the deviation.The modelling low voltage micro-grid was built. The simulation results of switching operating modes and cutting or increasing load in islanding mode can verify the accuracy of the improved droop control strategy of battery and the stability of the micro-grid operation.