As the increasing of the capacity of the micro grid, it is difficult for a single VSG-controlled inverter to meet the requirements of micro grid use. VSG operating in parallel has become the main solution, and the problem of equalization in the division has naturally become the focus of research. In this paper, the virtual impedance is introduced at first. Then, the principle of equalization is analyzed. A virtual impedance adaptive algorithm is designed. The value of the line impedance will be calculate in real time, and the adaptive virtual impedance automatically balance the differences of each lines, that will solve the problem of equalization bitterly. Finally, Matlab/simulink simulation is carried out under various working conditions to prove the validity and correctness of the proposed algorithm.