With the development of power electronics technology，microgrid type energy storage inverters with virtual synchronous generator（VSG） function have also been widely used. In VSG technology，due to the presence of inertial frequency regulation loop and voltage regulation loop，the inverter can realize the grid frequency regulation and voltage regulation function independently when it is connected to the grid，and it can realize the parallel power without communication when it is off-grid. However，in the microgrid system，due to the access of load and transformer，the parallel black start technology is one of the urgent problems to be solved when the inverter is off-grid. Through theoretical simulation analysis，an industrial frequency synchronous soft start method was proposed，which can realize smooth bus voltage establishment. The parallel power equalization of two VSGs during the soft start process achieved the completion of the black start of the whole system. Finally，the effectiveness of the parallel VSG black start control strategy was verified through experimental analysis.