The invention relates to a marine photovoltaic platform and an operating method of the marine photovoltaic platform. The marine photovoltaic platform comprises a base body and a plurality of hinges arranged around the base body, wherein the base body comprises a bowl-shaped water collection part, a cylindrical floating part and a cone-shaped gravity part for stabilizing the gravity and adjusting the buoyancy force of the platform from top to bottom; one end of each of the hinges is articulated with the periphery of the water collection part, and the upper surface of each hinge is provided with a plurality of photovoltaic panels; and the hinges can be enclosed with the water collection part after rotating along articulated points to form a sealed cavity. According to the marine photovoltaic platform and the operating method of the marine photovoltaic platform, marine photovoltaic power generation equipment is used for carrying out sealing to be isolated with the outside in the period of time that solar power cannot be utilized for power generation at night, so that the time that the photovoltaic power generation equipment is eroded is reduced; and due to the fact that the night approximately accounts for half of the whole day, the time that the photovoltaic power generation equipment is eroded can be effectively reduced by half, so that the service life of the photovoltaic power generation equipment is greatly prolonged.