This paper aims to explore the stress relaxation characteristics of TC11 titanium alloy. The finite elementmethod was adopted to simulate the laser shock peening and stress relaxation processes, and to analyze the influence of power density, number of impacts, and temperature on the stress relaxation of TC11 titanium alloy. The SIA–LSP–23 series laser shock peening system and the KSL–1700X–A2 high-temperature furnace were used to conduct laser shock peening and stress relaxation tests. When the temperature was 573 K, the power density was 5.09 GW/cm², and the number of impacts was 1 or 3, the error between the experimental data and the simulation results was less than 5%, indicating a good agreement between the simulated and  xperimental residual stress values. At a relaxation temperature of 573 K, an increase in power density had a greater effect on improving the stress relaxation limit than the number of impacts. However, the stress relaxation limit basically stopped changing after reaching 159.5 MPa, and it decreased as the temperature increased.