The invention discloses a waste collection device for a 3D printer. The waste collection device comprises a 3D printer rack and a fixed plate arranged on the side wall of the inner chamber of the 3D printer rack, wherein a plate-structured printing platform is embedded in the middle of the fixed plate; one end of the printing platform is rotationally connected with the fixed plate through a connection rotating shaft; a first electric push rod is arranged at the end, close to the connection rotating shaft, of the surface of the printing platform, and a first pushing plate is mounted on a push rod of the first electric push rod; a horizontal mounting platform is mounted on the side wall of the 3D printer rack, a lifting electric push rod is vertically arranged on the surface of the mountingplatform, and a push rod of the lifting electric push rod is rotationally connected to the bottom end of the printing platform; a storage box is arranged at the bottom of the inner chamber of the 3D printer rack. The waste collection device for the 3D printer is reasonable in structural design and worth popularizing and applying.