A method of state evaluation based on data fusion is proposed for the difference of test mode, admixture of quantitative and qualitative test information in the electromechanical equipment. The decision level fusion had been used in the state evaluation of electromechanical equipment by using D-S evidence theory. The theory analysis and the simulation results show that it is feasible and effective that the data fusion technology was applied on the state evaluation of electromechanical equipment. The results fused by different testing reduce the fuzziness of judgment and raises the reliable of state evaluation.