The surface of 316L stainless steel was melted by fiber laser. The effect of laser surface melting on the microstructure and wear resistance of 316L stainless steel was studied. Results show that a 500 μm thick layer with good metallurgical quality and free crack can be obtained on the surface of 316L stainless steel by laser surface melting. Compared with the original sample, the gradient refinement structure of equiaxed crystal, dendrite and columnar crystal is formed in the surface layer from top to bottom, the microhardness is increased by 73.9%, the friction coefficient is reduced by 37.8%, and the wear loss is reduced by 38.5%. The wear mechanism changes from abrasive wear and adhesive wear to slight abrasive wear, which indicates that the wear resistance of the substrate is significantly improved after laser surface melting treatment.