Abstract: In order to accurately and real-time respond to the dynamic changes of power grid emergencies and improve the timely response ability of power grid enterprises. Based on the analysis of the elements of the emergency system of power grid enterprises, the evaluation index system of power grid emergency capacity is constructed. From the perspective of dynamic characteristics and static characteristics to invite experts to score the evaluation indicators, the analytic hierarchy process is used to determine the subjective weight of the index, then the Bayesian network is constructed by using the previous data of power grid enterprises to determine the objective dynamic weight of the index, finally comprehensive dynamic weight and vague set model are combined to evaluate the power grid emergency capacity. The application of the dynamic evaluation method shows that this method realizes the real-time dynamic change of the emergency capacity of power grid enterprises, can better reflect the actual problems, and draw accurate and scientific conclusions.