The current distribution network of single-phase grounding fault detection model knowledge expression ability is poorer, the production process on the basis of normal distribution network sample data, only need single phase ground fault data, did not make full use of prior knowledge, lead to low accuracy.New power single-phase earth fault automatic detection model is put forward.Power single-phase earth fault feature extracting, the design of distribution network automated testing model of single-phase earth fault fault feature vector as input vector, the introduction of input vector and weight vector elements, the matching degree between them as the second node of the input and the output of the second layer as the third layer of input, was carried out on the model training, the output is the result of the distribution network of single-phase grounding fault detection results.The experimental results show that the proposed model is of high precision.