Abstract: During the welding process, shielding gas plays a critical role in determining weld quality. The use of shielding gas with different ratios leads to variations in the final weld quality. To ensure welding stability and achieve high-performance, high-quality welds, this study employs the controlled variable method to design different gas ratios (Ar-CO₂) used on-site, investigating their effects on weld appearance formation and microstructure-mechanical properties. The results show that the Ar-CO₂ ratio of 83: 17 exhibits superior bead appearance compared to 92: 8. While the microstructure and mechanical properties of both ratios show minimal differences, the 83: 17 ratio demonstrates a slight improvement in overall performance.