Abstract: Objective This study aimed to explore the influence of high-temperature creep on the residual stress in welded thick titanium alloy plates and to improve the prediction accuracy of the corresponding numerical model. Methods Based on the thermo-mechanical coupling theory, the welding temperature field of a Ti80 butt-welded plate was first calculated using the ABAQUS finite element software. Subsequently, the residual stress field was computed separately with and without considering the high-temperature creep characteristics, and the simulation results were compared with and verified against experimental data from the literature. Results The results indicated that the simulation results were in good agreement with the experimental ones. After considering the high-temperature creep effect, the change in the peak longitudinal residual stress was within 5% compared with the case neglecting creep. However, the peak transverse residual stress along the weld direction decreased by approximately 40%, accompanied by a tensile-to-compressive stress transition at both ends. The transverse residual stress perpendicular to the weld direction at the weld center decreased by about 80%. Conclusion Incorporating the high-temperature creep effect can effectively improve the prediction accuracy of the numerical model for residual stress in thick titanium alloy plate welding.