The invention discloses a steel sheet clamping device for laser cutting. The steel sheet clamping device comprises a base, a first bump, an upper pressure plate, a second bump, a guide post, a compression spring, a wedge block and a waste box. The device can conveniently clamp and fix a steel sheet and can realize position adjustment and unloading of the steel sheet; the operation is convenient, the working efficiency is high, the flatness and stability of the steel sheet are guaranteed, and the cutting quality is high; and moreover, through a waste tank at the lower end of the base, the waste can be conveniently cleared and recycled, and the whole laser cutting device is protected from smog. The device has the advantages of simple structure, convenience in operation, high processing efficiency and high processing quality.