Abstract: Based on hot compression experiment, the dynamic recrystallization (DRX) behavior of 25MnB steel at the deformation temperatures of 850-1150 ℃ and the strain rates of 0.01-30 s-1 was studied. Then, the critical strain of its DRX was solved by the theory of work hardening rate, and the critical strain model was established. Furthermore, based on Avrami model, the DRX dynamics and grain size evolution laws were described, and these models were embedded into finite element model software DEFORM-3D to achieve visual simulation of DRX behavior for 25MnB steel. The simulation results indicates that the evolution of equivalent strain and equivalent strain rate for 25MnB steel samples exhibits non-uniformity, and the degree of DRX is dependent on the distribution of equivalent strain. The deformation conditions have a significant impact on the evolution of DRX volume fraction and grain size. With the decreasing of temperature and the increasing of strain rate, the complete DRX occurs in the central region, and the grain size is significantly refined. However, due to the insufficient local DRX phenomenon, the non-uniformity of grain size distribution on the same cross-section is also increased. The finite element simulation results of DEFORM are in good agreement with the experimental results, providing a basis for the microstructural evolution prediction of 25MnB steel during the hot stamping process.