The invention relates to a single-phase fault line selection method of a low current grounding system. Wavelet decomposition is carried out on the zero-sequence current of feed lines to obtain wavelet energy of the feed lines, a sample set is established according to the obtained wavelet energy, and the sample set is normalized to obtain a normalized sample set X*. The Spiking neural network is established initially by utilizing an SRM neuron model, the weights of synaptic units among the neurons in the input layer H, neurons in the hidden layer I and neurons in the output layer J are calculated in the SpikeProp method, the connection weights are corrected to obtain the line section Spiking neural network, fault data is input to the line section Spiking neural network, and a line with the mark phi0 output by the output layer is determined to be a fault line. Operation is convenient, whether a grounding fault occurs in the electrical network is determined rapidly and effectively, the line with the grounding fault is determined after that the grounding fault is determined, and basis is provided for eliminating the fault timely.