Abstract: In order to explore the application of 316L stainless steel ultra-thin sheet in heat exchanger, metal pole sheet and other fields, a pulsed laser was used to perform laser welding process experiments for 0.15mm thick 316L stainless steel sheets, and the microstructure and mechanical properties of the welded joints were analyzed. The results show that when the laser power is 90 W, the welding speed is 25 mm/s, the pulse frequency is 90 Hz, and the laser focal length is -1.5 mm, a welded joint with single-side welding and double-side forming, smooth and defect-free surface can be obtained. The weld zone is composed of fine equiaxed crystals and the hardness is higher than that of the base metal zone.The tensile strength of the welded joint is about 539.5 MPa, reaching 86.8% of the base metal, and the elongation after fracture is about 30.5%, reaching 75.7%of the base metal.