Provided is a laser welding construction device. On the basis of the acting force of the electro-permanent magnet field on workpieces, magnetic force penetrates through stainless steel so that clamping force can be generated and work can be achieved, the assembly gap between two workpieces can be eliminated, it is guaranteed that the workpieces are closely attached, the workpieces are restrained all the time in the laser welding process, and influences of the assembly gap on the laser welding quality are eliminated. The laser welding construction device comprises an electro-permanent magnet disk, magnetic conductive gaskets and auxiliary pressing blocks, wherein the electro-permanent magnet disk is laid on a supporting platform, the magnetic conductive gaskets are laid on the electro-permanent magnet disk, the workpieces are laid on the magnetic conductive gaskets, the auxiliary pressing blocks press the upper portions of the workpieces, the electro-permanent magnet disk is connected with an electronic control system so that demagnetization and magnetization can be achieved, the workpieces are released when demagnetization is performed, and the workpieces are clamped when magnetization is performed. The laser welding construction device can generate different clamping forces according to the different auxiliary pressing blocks, different plate thickness combination penetrating capacity and different magnetic field density tests so that the workpiece assembly gap can be controlled. The laser welding construction device further has the effects of being capable of improving assembly efficiency and saving upper welding space.