Abstract: The microstructure difference of 15% SiC_p/Al composite spot welded joints between direct spot welding and spot welding with stainless steel sheet addition was studied.The joint microstructure, tensile-shear fracture and generation mechanism of welding spatter were analyzed.The results show that segregation of SiC particles appears in the nugget zone of the direct welded joint; when it is welded with the interlayer of 0.12 mm stainless steel sheet added between the SiC_p/Al composite material and the electrode, the SiC particles are evenly distributed in the nugget area, the weld zone is dense without porosity, inclusions and crack defects.When the spot welded joint is torn apart, the welded joint fracture is a button-shaped fracture, and the joint is well formed.When the welding process parameters are improper selected, the weld liquid metal has obvious spillover, the welding spatter occurs.