It had been studied that thermal deformation properties of AerMet100 steel (AMT100) by thermal simulation on Gleeble 3500 Simulator, which the ranges of temperature and strain rates were 900～1100°C and 0.01～10/s. According the experiment data, the parameters of thermal deformation was calculated, in which the activation energy is 261.2KJ/mol. The strain-rate sensitivity coefficient is m=0.0998, and temperature sensitivity coefficient is s=7912. The relationship among peak stress and deformation temperature and strain rate was established. And the ranges of temperature and strain rates were 900～1100°C and 0.01～10/s, and the relative errors of calculation results by the stress-strain model were less than 11.3%.