The invention discloses a method for molding gradient materials by interlayer laser improved selective laser melting. A laser surface modifying process is integrated with a selective laser melting process; and through a laser modifying mode for rescanning of molded parts by laser beams after molding of a certain number of lasers through selective laser melting at each time, microscopic structuresand performances of different areas of the parts are changed to obtain high-performance parts with different performances and gradients. Meanwhile, through rescanning by the laser beams, such defectsas holes in the layers, micro cracks and surface projections can be eliminated, so that the compactness and the surface quality of the molded parts are improved. The structure and performance change of the parts can be realized through modes of adjusting the set layer number, the laser rescanning power, the laser beam scanning speed and the laser beam scanning gap. When the compactness of the molded parts is improved, the direct molding of multi-performance gradient materials by the selective laser melting technology is realized, and a significant effect on promotion of the industrial technology development is achieved.