Abstract: Multi-parameters have impact on the weld geometry during triple-electrode high speed CO₂ welding. All the parameters cannot be considered at one time. Therefore,the main parameters should be studied during the welding process. In this paper,two kinds of factors such as welding power and welding speed of three levels were studied to predict the weld geometry parameters by statistical method. The results show that the horizontal leg length,vertical leg length and the convexity degree are affected by the main effect. The predicted value of vertical leg length is 4 mm,the horizontal leg length is 2.5 mm, and the convexity degree is 2.5 mm.