Abstract The microstructure and mechanical properties of aluminum and brass welding joints were investigated. The microscopy image revealed that the welding interface was flat in the case of using lower laser pulse energy. When the laser pulse energy was higher than 1200 mJ, the wavy interface and local melting blocks were created simultaneously. Quantitative analysis conducted by energy dispersive spectroscopy revealed that intermetallic compounds were generated in the melting blocks. Energy dispersive spectroscopy line scan analysis indicated that slight element diffusion occurred at the welding interface. The tensile shear test results demonstrated that the failure load of welding joints showed an upward trend as laser pulse energy increased. The maximum failure load of welding joints reached approximately 62% of the tensile failure force of the base metal. Spalling and fracture failures were observed respectively in tensile shear test. Spalling failure occurred only at 565 mJ laser pulse energy. Fracture failure occurred on the side of aluminum when the laser pulse energy was higher than 835 mJ.