This paper investigates the effects of welding voltage, welding current, wire feeding speed, travelling speed and welding position on aspect ratio, dilution rate, microhardness and fluctuation using orthogonal experiment design. To achieve multi-objective optimization, S/N ratio conversion and grey relational analysis were employed, The model-predicted process parameters were then verified. The study findings indicate that the welding position has the greatest impact on aspect ratio, dilution rate and fluctuation, while the welding current has the greatest impact on the microhardness. Additionally, the force of the droplets at different positions affects the average aspect ratio and fluctuation, the arc shape affects the dilution rate, and the heat input affects the microhardness. Furthermore, the arc shape at different positions exhibits distinct characteristics. Finally, the optimal process parameters for different positions were obtained through an orthogonal test. The optimal combination of process parameters was found to be 70 A for welding current, 25 V for welding voltage, 500 cm . min −1 for wire feeding speed, 50 cm . min −1 for travelling speed, and vertical up welding position. The experimental results indicate that the optimized process parameters can consistently improve the welding quality, with a relative error of only 2.38% of only 2.38% between the grey relational degree and predicted value. This study's findings hold significant practical value for enhancing welding process stability and quality.