TA32 titanium alloy has better creep resistance than TC4 titanium alloy at high-temperatures, which is widely applied in the hypersonic aircraft. It is challenging to meet the dimensional requirements for the complex components of TA32 titanium alloy due to the springback after hot forming. The stress relaxation behavior of TA32 titanium alloy was studied at different temperatures (650 ℃, 700 ℃, 750 ℃, 800 ℃) and pre-strains (2%, 4%, 8%). With the increasing temperature, the stress relaxation rate at the first stage increases, and the limit of stress relaxation decreases. Based on the experimental data, the explicit constitutive equation of stress relaxation was fitted with the quintic delay function, and the Arrhenius type creep constitutive model was established. Considering the effect of high-temperature stress relaxation, the hot forming simulation model of a TA32 titanium alloy reinforced frame was established, and hot forming and springback test verified the reliability of the simulation model. The results show that the springback can be effectively reduced due to holding process. With the holding time increasing from 10 s to 1800 s, the springback decreases from 3.15 mm to 2.55 mm. When the holding time reaches 300 s, the stress reaches to the relaxation limit, and the springback is almost unchanged.