The invention belongs to immersed pipe tunnel construction and discloses a material backfilling system. The material backfilling system comprises a hull and a locking backfilling system which is arranged on the hull; the locking backfilling system comprises two chute pipes and a feeding module; the chute pipes are arranged on one side of a shipboard of the hull and can move; the feeding module is connected with the chute pipes. According to the material backfilling system, the hull is provided with the chute pipes which can move and the feeding module which is connected with the chute pipes, and accordingly the feeding can be performed on the chute pipes, the locking backfilling can be performed on an immersed pipe tunnel through the chute pipes, the positions of the immersed pipe tunnel can be backfilled due to the mobile chute pipes, the integral firmness and stability of an immersed pipe is ensured, and the safety of the immersed pipe tunnel is improved.