Abstract: Aiming at the welding defects occurring in the aluminum sheath weld of high-voltage cables, the process characteristics and key parameters of tungsten inert gas (TIG) welding for aluminum sheaths were analyzed. Welding current, welding speed, and helium flow rate were selected as the three key factors based on the significance of their influence on weld quality. The orthogonal test method was employed to investigate the effects of these three factors at three levels, and the process parameters of TIG welding were optimized. Combined with range analysis, the optimal parameter combination was determined. Experimental results demonstrated that after optimization, the average tensile strength of the aluminum strip was increased to 70.4 N·mm^–2. Meanwhile, the optimized parameters ensure the required weld strength without causing excessive thermal impact on the insulation layer, and the welding quality meet the performance requirements for the metallic sheath weld of high-voltage cables. The study also validated the effectiveness of the orthogonal test method in the optimization of welding process parameters.