The dynamic recrystallization (DRX) behavior in the isothermal hot compression of AISI 52100 steel was analyzed by using the phenomenological-based cellular automaton (CA) algorithm. The developed CA model was coded into DEFORM platform, which is a Finite Element Method (FEM)-based software for simulation of material deformation process. The developed CA-model can thus predict the nucleation and growth kinetics of dynamically recrystallized grains of the testing material in hot working process. Furthermore, the effects of the deformation temperature, true strain and strain rate on the microstructural evolution of the testing material were physically studied by using Gleeble-1500 thermo-mechanical simulator and the developed CA-model was verified by the experimental results. Through simulation and experiment, it is found that the results predicted by the CA-model have a good agreement with the experimental ones.