The performance of load distribution is critical for the stable and efficient in an autonomous microgrid with multi-inverter parallel system. Through in-depth analysis of the load distribution mechanism of multi-inverter parallel system, the conclusion that the mismatch of rated power with line impedance is the root cause of inaccurate distribution is got. On this basis, a method based on the introduction of virtual impedance is proposed to achieve the match of rated capacity of the inverter with the total output impedance, in order to achieve the purpose of improving the load distribution properties. At the same time, the droop characteristic curve is corrected to reduce the impact of virtual impedance on the output voltage. Finally, The effectiveness of the proposed control strategy is verified on the Matlab/Simulink simulation platform.