The utility model belongs to the technology of an overwater building and discloses a feeding backfilling boat. The feeding backfilling boat comprises a boat body, a material delivery system and a locking backfilling system, wherein the material delivery system and the locking backfilling system are arranged on the boat body. The material delivery system comprises a discharging module and a multilevel material lifting delivery module which receives materials supplied by the discharging module and delivers the materials. The materials are lifted by the multilevel material lifting delivery module for multiple levels to a preset height and delivered to a leveling boat. The locking backfilling system comprises two movable elephant trunks arranged at one side of a boat rail of the boat body and a feeding module connected with the elephant trunks. A feeding boat and a backfilling boat are arranged into a whole, a feeding function and a backfilling function are achieved simultaneously through one boat body, and the cost of devices used in the process of tunnel construction is reduced. The materials are lifted by the multilevel material lifting delivery module for the multiple levels so that the materials can reach the preset height. Due to exist of the multilevel lifting, an inclined angle of each belt conveyor used in the lifting of each level is not large, and material delivery efficiency is improved.