Abstract: Through isothermal hot tensile experiments, the hot deformation behavior and microstructure evolution laws of 304 austenitic stainless steel under the conditions of the high temperature of 650-1100 ℃ and the strain rate of 0.001-0.1 s-1, and the strain hardening constitutive equation was established. The results indicate that the microstructure of 304 austenitic stainless steel  is mainly composed of austenite, and a large amount of M23C6 carbide phases are precipitated at the deformation grain boundaries below 800 ℃. The dynamic recrystallization mainly occurs in deformed materials above 950 ℃, and the size of the recrystallized grains increases with the increasing of deformation temperature. The rheological behavior of 304 austenitic stainless steel is sensitive to deformation temperature and strain rate, and the rheological stress decreases with the increasing of deformation temperature and the decreasing of strain rate. In addition, long-period strain hardening behavior is exhibited in 304 austenitic stainless steel. Based on the strain rate hardening effect and strain hardening effect of materials, a strain hardening constitutive equation with high prediction accuracy was established considering the temperature compensation. The correlation coefficients of models under various deformation conditions are all more than 95.12%, and the average absolute errors are less than 10.48%.