The invention provides a power grid operation risk evaluation method and a system based on an entropy weight method. The method comprises the following steps: establishing a power grid operation safety risk evaluation system; determining the weight of each evaluation index by using an entropy weight method, establishing a judgment matrix of the evaluation indexes of the evaluated object and standardizing the judgment matrix; normalizing the judgment matrix to obtain a normalized judgment matrix; determining the entropy of the evaluation index in the evaluation problem of the evaluation index of the evaluated object; determining an entropy weight of the evaluation index according to the defined entropy of the evaluation index; obtaining an evaluation index weight vector based on the entropyweight; and evaluating the power grid operation risk level by using the matter-element model. The risk assessment model is established through modeling analysis in combination with the entropy weightmethod and the matter-element model, qualitative analysis to quantitative analysis is achieved, the simple and easy-to-calculate power grid operation personal safety risk quantitative practical assessment method is given, and a power grid company is effectively assisted in conducting pre-control management on personal safety risks of power grid operation.