Abstract: High-temperature compression tests under differenct deformation temperatures （1223, 1323, 1423, 1523 K） and strain rates （0.01, 0.1, 1.0, 10.0 s⁻¹） were conducted on 310S austenitic stainless steel. The dynamic softening behavior of the steel was studied. A criterion of critical strain for dynamic recrystallization based on dislocation annihilation mechanism was established The recrystallization fraction prediction model considering strain distribution effect was constructed, and the predication was analyzed. The results show that the core dynamic softening mechanism of the test steel under experimental parameters was dynamic recrystallization. When the deformation temperature was relatively low （1223−1323 K）, the microstructure showed incomplete recrystallization characteristics, with a bimodal distribution of coarse parent phase grains and dispersed fine grains, and the proportion of parent phase grains was relatively high at relatively high strain rates. When the deformation temperature was relatively high （1423−1523 K）, the microstructure approached or nearly approached complete recrystallization. The dynamic recrystallization volume fraction obtained by the dynamic recrystallization volume fraction prediction model was positively correlated with the deformation temperature and negatively correlated with the strain rate, which was consistent with the experimental results. The predicted values of the dynamic recrystallization volume fraction after compression under different parameters also corresponded to the observed microstructure characteristics in the experiments.