An enhanced control method of real-time power dispatch is proposed to improve the system security in case of the total transfer capability（TTC） of certain interfaces lower than its margin. Improving the TTC is taken as the object in this method， which can cope with different situations， such as one or more interfaces exceeding the TTC margin. In particular， this method can provide a valuable Pareto solution for the multiple interface case. The feasibility and applicability of the proposed method are proved with the numerical tests of IEEE 39-bus system and an actual power system in Central China.