Abstract: Aiming at the welding problem of automobile power battery tabs, the single control variable method was used to study the influence of laser power and welding speed on the surface morphology and cross-sectional topography of the weld of automotive power battery aluminum tahs and aluminum busbars. The hardness and shear resistance under different welding parameters were measured to study the influence of welding parameters on mechanical properties and the optimal welding parameters were determined. The research results showed that the increase of laser power and welding speed caused the gradual blurring of fish scales, the size and number of cross-section pores and the shear resistance reduced after rising. A positive association was discovered between hardness and welding speed, while laser power was negatively correlated with hardness. When the laser power was 650 W and the welding speed was 55 \mathrm~mm / \mathrms, the weld quality was the best, the fish scale phenomenon was obvious, the center hardness of the weld was about 36 HV, and the shear resistance was 765.41 N. This research had practical guiding significance for the optimization of the welding process of aluminum tabs and aluminum busbars of automotive power batteries.