In order to further simplify the process of economic loss assessment of voltage sag and improvethe applicability and accuracy of economic loss prediction, an estimation model based on DBN-DNN for economic loss caused by voltage sag is proposed. The characteristic factors affecting theeconomic loss of voltage sag are analyzed The 19-dimensional feature vectors are extracted from the saginformation, industrial process information, sensitive equipment information and users’ basic information asinput vectors of DBN-DNN prediction model, and the economic loss results are taken as output. Finally, the DBN-DNN model is trained and evaluated based on the actual voltage sag sampling data of alarge electronic industry enterprise in China, which shows the effectiveness of the proposed method.