In view of the low efficiency of periodic maintenance of secondary equipment in the current power grid, and the evaluation results are too dependent on the subjective experience of experts, a risk assessment method for the operation status of secondary equipment based on association rule mining and combination weighting-cloud model is proposed. First, based on the Apriori association rule mining algorithm, the evaluation index is screened, and the risk evaluation index system for the operation status of the secondary equipment is constructed. Secondly, the attribute analytic hierarchy process and the anti-entropy method are used to calculate the subjective and objective weights of the evaluation indicators, and the combined weights are obtained based on the cooperative game model. Finally, a secondary equipment risk assessment model is built based on cloud model based on cloud theory. Example analysis shows that the method is simple and easy to implement, improves the scientificity and accuracy of the evaluation results, and assists the operation and maintenance personnel of the secondary equipment of the power grid to make scientific and reasonable maintenance decisions. This work is supported by the National Natural Science Foundation of China (No. 51667020).