Abstract: The ultra-high frequency pulsed gas tungsten arc welding process was optimized by response surface method(RSM). By establishing the functional relation, the regression model of weld bead size on welding current(I_b), wire feed speed(WFS) and travel speed(TS) is obtained, and the reliability of the regression model is verified by variance analysis. The corresponding welding parameters are selected by setting the optimization conditions and the size of weld bead is predicted. The error between the predicted size from the model and the actual size is 5.4% of bead width and 6.6% of bead height, respectively. After the deposition of thin-wall GH4169 superalloy part, the mechanical properties are tested, including the horizontal and vertical tensile properties, the ultimate strength are 1 130.93 MPa and 1 126.04 MPa, respectively, the elongation rate are 18.1% and 16.56%, respectively, the reduction of area are 20.6% and 20.2%, respectively.