Abstract: AlSi10Mg aluminum alloy has the characteristics of low density and high specific strength, and it is widely used in the field of lightweight structure. However, the size of parts formed by selective laser melting is still limited by the forming chamber. The butt welding between 3 mm thick selective laser melting AlSi10Mg aluminum alloy and 2A70, 6061, 5A06 aluminum alloy rolling materials, respectively, was realized by laser self-melting welding technology, and the weld morphology and tensile properties were analyzed. The results show that the surface forming quality of butt welds of aluminum alloys is good, and there are no defects such as cracks and undercuts, but there are pore defects in the welds. The pores are mainly process pores and metallurgical pores. The high solidification cooling rate of laser welding makes the grains grow almost perpendicular to the fusion line. From the base metal area to the weld area, there is a transition from granular eutectic silicon to network eutectic silicon.The tensile strength of AlSi10Mg laser welded joints reaches above 70% of that of the base metal with low strength. There are quasi-cleavage steps in the fracture of each weld tensile specimens, and no significant necking phenomenon is observed in the specimens. The macroscopic fracture mode is brittle fracture.