A physical model for austenite recrystallization of steel concerning TMCP is developed. Dislocation density plays a key role as recrystallization driving force. The dislocation density change is a result of competition between dislocation generation and dynamic recovery. Recrystallization is described as a nucleation-growth process. An abnormal subgrain growth mechanism is introduced for nucleation. A few subgrains fulfilling abnormal growth conditions will stand out and become nuclei of recrystallization. The recrystallized grain grows to the deformed materials driven by the stored energy. Oswald ripening occurs for grains surrounded by recrystallized grains. The models were verified by laboratory simulation results for selected austenite stainless steels. It showed good agreement between predicted and experimental results.