A pulsed wave Nd:YAG laser is used to weld copper and 316L stainless steel. The microstructural characteristics and interfaces of the welded joints by different laser lap welding of copper and 316L stainless steel are investigated to search for the suitable welded joints and then analyze their mechanical properties. Optical microscopy and energy dispersive spectroscopy (EDS) are used to observe the interface of the welded joints. X-ray diffraction (XRD) is used to analyze the phase of the interface. Scanning electron microscopy (SEM) is used to observe the fracture surface morphology of welded joint. Microhardness and tensile testing are used to analyze the mechanical properties of the welded joints. Results show that intermetallic compounds are absent in the welded joints because copper and stainless steel exhibit unlimited solid solubility. The welded joints with the copper on stainless steel overlap configuration show better microstructure and mechanical performance.