The invention discloses a DNN-based low-voltage transformer area line loss rate benchmark value setting method in the technical field of line loss rates, aims to solve the technical problem of lack oftransformer area line loss rate benchmark value indexes in the prior art, collects transformer area operation data based on an existing power utilization management system, and screens out influencefactors of a transformer area line loss rate. Correlation analysis is carried out on the line loss rate of the transformer area, and line loss rate key factors influencing the line loss rate are extracted; modeling the key factor and the transformer area line loss rate based on a deep neural network algorithm, and calculating a benchmark value of the transformer area line loss rate; and adjustingthe transformer area with abnormal line loss according to the calculated transformer area line loss rate benchmark value. Key factors influencing the line loss rate are extracted on the basis of actual operation data, and a low-voltage transformer area line loss rate benchmark value calculation model is established through the DNN. The benchmark value of the line loss rate of the low-voltage transformer area can be given, a ruler is provided for line loss of various transformer areas, and the loss reduction direction is clear.