Abstract: Conventional frequency conversion power supply can achieve independent power supply function, but cannot meet the requirements of seamless power supply. Before the frequency conversion power supply for the ship to provide power, the ship’s main power generation unit must be stoped firstly. On the contrary, it is necessary to stop the power supply system of variable frequency power supply, and then to restore the power supply of the ship generator. In this paper the multi-level parallel shore power technology system is focused on, and by using the micro-grid application design of variable-frequency shore power system, simulating the working principle of ship generator, the voltage and frequency of power grid real-time detection of ship detection sensor, real-time adjustment of system output voltage and frequency of power source, to achieve the synchronization, so as to realize the seamless grid power supply functions of frequency and shore power supply system.