The present invention provides a device and method for degating of an aluminum wheel blank by laser cutting, and the device comprises members including a lower lifting frame movable long beam, a middle lifting frame inner side oblique beam, a middle lifting frame pin shaft, a rubber supporting cushion, an upper lifting frame long fixed beam, a middle lifting frame outer side oblique beam, a first stroke limiting frame, a first stroke limiting wheel, a second stroke limiting frame, a second stroke limiting wheel, piston firm retaining rings, frame-shaped guide plates, directional sliding blocks, grating positioning devices, a wheel blank member, a roller way, a lower rack fixed frame, a lower gate taking device fixed frame, a laser cutting head, an eccentric turning wheel, high-temperature-resistant resin clamping gaskets, clamping blocks, rack vertical corner frames, clamping hydraulic cylinder pistons, horizontal clamping hydraulic cylinders, a movable plate and the like. When in use, the device of the present invention can realize the function of online removal of a wheel gate, can improve work efficiency, can also reduce labor force, and has the characteristics of high cutting precision, round and burr-free cutting position, stable performance, high degree of automation and the like.