To optimize the process parameters of inertia friction welding for small，thin-walled annular workpieces and to investigate the relationships between these parameters and joint geometry as well as axial shortening，a two-dimensional axisymmetric，thermo-mechanically coupled finite-element model was developed in ABAQUS.Using the tensile strength of the welded part as the response variable，a Box-Behnken experimental design was employed within a response surface methodology（RSM） to construct a regression prediction model，which was subsequently validated by experiment.The results show that the quadratic polynomial regression model fitted via RSM is statistically sound，with a significance P-value0.000 1 and a lack-of-fit value 0.05.The optimized parameters are an initial speed of 380 r/min，a friction pressure of 268.93 MPa，and a moment of inertia of 350 kg·m².The discrepancy between experimental measurements and model predictions is within 5%.