This paper presents a risk-based method for coordinating generation rescheduling and load shedding to enhance overall transient stability of power systems. Firstly, a generation rescheduling model that can consider the risk-based dynamic security constraint is proposed, in which some acceptable risk level should be respected and can be adjusted by a risk coordination parameter. For the purpose of considering the potential corrective control costs at the stage of preventive control design, a bi-level coordination optimization model is developed, in which on the upper level the total coordination cost is minimized by the risk coordination parameter adjustment; and on the lower level the generation rescheduling and the load shedding are performed successively to enhance the risk-based dynamic security and the transient stability performance, respectively. Finally, a hybrid method that can combine the Golden Section Search and the Successive Linear Programming is developed to solve the bi-level optimization model. The effectiveness of the proposed method is demonstrated by using the New England test system and a real power system. © 2013 IEEE.