The invention relates to the technical field of intelligent power consumption, in particular to a system and a method for controlling a ship power supply system in a port to participate in a demand response, more specifically to the system and the method for controlling the ship power supply system in the port to participate in a power demand response. According to the system, a ship is connected with a central control room host through a bus; the present remaining amount of a battery of the ship and related information of port time and expected port-leaving time are transmitted to the central control room host; the central control room host makes a reasonable instruction according to the information transmitted by a monitoring unit; a circuit of the ship power supply system is controlled; and the central control room host in the ship power supply system and a demand response master station of a power system carry out information interaction through a power line. According to the system and the method, safe and effective transmission of a power demand response event is ensured; and meanwhile, the condition that the ship power supply system participates in the demand response is relatively efficiently and economically achieved by an existing monitoring system of the ship power supply system.