How to improve the economic performance of power system operation while maintaining its security is the key issue of short-term generation scheduling. To overcome the deficiency of the previous preventive unit commitment and unit commitment methods considering corrective control， a corrective security constrained unit commitment method is proposed. This method can consider the corrective control ability of real-time operation precisely， and significantly extend the optimization space with a certain security level. Based on the essence of corrective control， a Benders decomposition method is proposed to improve the problem solving efficiency. This algorithm can simultaneously consider the unit status and its power output， therefore requires less iterations and computation time. Theoretical analysis and experiment results validate the effectiveness of the proposed model and algorithm.