Abstract： The dynamic recrystallization behavior of low carbon steel under ESP process was simulated by using MMS-200 thermal simulation tester. Considering the influence of austenite grain size change before deformation, the dynamic recrystallization mathematical model was established. The results show that: the initial microstructure under ESP process condition can be simulated by austenitizing at 1350℃ and holding for 300s, and the larger the initial austenite grain size, the more difficult dynamic recrystallization is to occur; the dynamic recrystallization activation energy increases with the increase of the initial austenite grain size, and the initial austenite grain size has no effect on the relationship coefficient s between peak strain and critical strain; considering the effect of initial austenite grain size, dynamic recrystallization activation energy model, peak strain model and dynamic recrystallization dynamic model of experimental steel were established. The research results lay a theoretical foundation for developing high quality thingage low carbon steel and improving the prediction model precision of microstructure properties under ESP process conditions.