It puts forward new requirements to strategy searching of emergency control considering multiple factors, such as intermittent energy access, the interconnection of national power grid, and requirement of operation protection and control online operation. This paper proposes an optimal searching method of the emergency control strategy based on greedy algorithm. This method does time-domain simulation by choosing a certain instability case of the expected fault set and calculates performance index of each emergency control measure based on the theory of quantitative analysis of EEAC, based on which calculates the price ratio of each emergency control measure in emergency control space. The key is to calculate variable quantity of transient stability margin before and after taking emergency control measures. Then it searches out the optimal emergency control strategy in candidate emergency control space through greedy algorithm. Finally, the correctness of the proposed method is verified by a simple power system and a real power grid.