The deformation resistance of siliconmanganese TRIP steel at different deformation temperature and strain rate is discussed. The stressstrain curve at deformation rate of 1 s-1, 10 s-1, 20 s-1, 75% deformation ratio and deformation temperature of 1 200 ℃, 1 100 ℃, 1 000 ℃, 900 ℃ and 800 ℃ is determined by Gleeble1500 thermalmechanical simulator. The deformation resistance results of TRIP steel are fitted by using software SPASS and the influence deformation condition on the deformation resistance is simulated, then the mathematical model formula is obtained. The average absolute error is less than 5 MPa, the average relative errors are less than 5 percent, the largest absolute error is less than 10 MPa, and the maximum relative error is less than 15%. These results show that the error is relatively small. The calculated results are in the permissible range. The experimental results show that the true stress is stable after 04 true strain. Below 1 100 ℃, work hardening is more obvious. The result shows that the temperature is lower, and workhardening rate (n value) is higher.