The invention relates to a prefabricated bearing platform suitable for a large-
diameter tubular column foundation of a sea bridge and a construction method of the prefabricated bearing platform. The prefabricated bearing platform is of a multi-box lattice type concrete structure, and a box chamber and the large-
diameter tubular column foundation are uniform in arrangement. Movable steel bottom plates are arranged at positions, corresponding to tubular columns, of bottom plates, and connecting reinforcing steel ribs are arranged on the inner wall of the prefabricated bearing platform. The construction method includes the steps of prefabricating the bearing platform in a
dry dock on the
bank side, filling the
dry dock with water after the bearing platform is prefabricated, enabling the prefabricated platform to float by itself, opening a lock when the
water level inside the dock is flush with the
water level of the sea surface, and dragging the prefabricated bearing platform to the position of a
pier; filling the prefabricated bearing platform with water so that the prefabricated bearing platform can sink onto a temporary support, and erecting an operating platform on the top of the prefabricated bearing platform; taking down the movable
steel plates, conducting tubular column sinking construction, pouring
underwater bottom sealing concrete, pumping water, bonding the reinforcing steel ribs, pouring bearing platform concrete, and forming a complete bearing platform structure. According to the prefabricated bearing platform and the construction method, platform erecting expenses can be saved, materials are used completely, construction investment and time are saved, and the prefabricating bearing platform can bear force together with later period bearing platform concrete.