In view of the problems of single transformer condition evaluation method and the complicated factors thataffected the performance of transformer

a state assessment method of transformer based on AHP（analytic hierarchyprocess

AHP）method and rough set theory is proposed. Combined with the experience of experts

the AHP methodis used to obtain the subjective weights of the components and state quantities divided by the hierarchical structure;By the test data of transformer

it is adopted to analysis the objective weight of each part and state quantities by roughset theory

the optimized combination weights

which is the combinatorial optimization of subjective and objectiveweights

reflected in the proportion of the parts

state quantities of the running state of transformers. The model is ap-plied to analyze the maintenance data of two different types of transformers and the results are compared with the ac-tual transformer maintenance status

it has proved that this model has the ability to evaluate the transformer statuscomprehensively and accurately.