The invention belongs to the field of wood processing, and particularly relates to a leftover material screening device for wood processing. The leftover material screening device for wood processingcan screen leftover materials of different sizes simultaneously, is high in screening speed, and is small in occupied area. The leftover material screening device comprises a mounting box, a collecting frame, a first L-shaped plate, a fixed pulley, a stay wire, a first fixing plate, a motor, a sector gear, a first rotating shaft, a first bearing pedestal, a rack, a first sliding rail, a first screening plate, a second fixing plate, a second screening plate, a third screening plate, a feeding hopper, a second sliding rail, a first elastic part, a first sliding block and the like, wherein the feeding hopper is fixedly connected to the top of the mounting box, and is communicated into the mounting box. The leftover material screening device can screen leftover materials of different sizes simultaneously, is high in screening speed, and is small in occupied area.