Based on ABAQUS finite element analysis software, a two-dimensional axisymmetric model of TC4 titanium alloy inertial friction welding (IFW) process was established.The thermal coupling analysis of TC4 titanium alloy by inertial friction welding was carried out by establishing Johnson-Cook damage model and ALE technique.It was found that TC4 inertial friction welding increased to about 200℃ to 300℃ in 0.2 s, up to 1 100 to 1 200℃ in 0.5 s and then reached to a flatten.After reaching the peak, the temperature droped slowly and the welding were completed. The axial shortening is very small within 0.6 s, and it increases very fast and reaches a peak substantially at temperatures of 1 100 to 1 200℃ (0.6 to 1.2 s),from 1.2 to 1.4 s axial shortening increases slowly due to cementation.The temperature no longer increases after 1.4 s, and the welding is completed and the axial shortening is no longer increased. The initial stage of axial stress basically unchanged, with increasing temperature (0.2 to 0.5 s) compressive stress increases in the central region. The stress concentration in the center is more obvious, after 1.2 s tensile stress increases significantly. The radial stress increases with temperature,center stress was significantly higher than the outside and the metal flow to both sides. This leads to the result that the flash formation is mainly due to the complicated effect of high temperature, axial stress and radial stress. The simulation results are basically consistent with the actual results, which can provide an important reference for improving the welding quality of inertial friction welding.