There are two kinds of micro-grid and off-grid working mode, to achieve seamless switching between the two modes of operation is to ensure the stable operation of the system key. Firstly, the system model and working mode of micro-grid are introduced. Then the seamless switching control technology based on virtual synchronous generator (VSG) and the seamless switching technology based on droop control are introduced respectively. Finally, The simulation model of the microgrid system is validated to verify the feasibility of the two control technologies. The control effects of the two handover processes are compared and analyzed. According to the simulation results, the seamless switching control strategy based on VSG is more applicable to the off-grid handover of the micro-grid.