The invention discloses a modular high-power shore power supply system. The shore power supply system comprises: an input control and confluence module, a shore power supply module, and an output control and current sharing sampling module; an input end of the input control and confluence module is connected with a three-phase alternating current phase of 380V/50Hz; an output end of the input control and confluence module is connected with the input end of the shore power supply module; the output end of the shore power supply module is connected with the input end of the output control and current sharing sampling module; the output end of the output control and current sharing sampling module outputs three-phase alternating current of 440V/60Hz; the shore power supply module comprises multiple 100kW shore power supply units having the same structure; and the output control and current sharing sampling module is used for performing current sharing control on the multiple 100kW shore power supply units to reduce the ring current among the 100kW shore power supply units. By adoption of the shore power supply system provided by the invention, derating operation during failure can beachieved, and the stability of the high-power shore power supply system can be improved.