The invention relates to an online distance measurement method of power cable malfunction bases on manual neural network model, to ensure the location of the power cable malfunction. The method's connects the three-phase current analog signals which is from the current transformer and the voltage transformer in both ends of the cable, zero order current analog signals and three-phase voltage analog signals, zero order voltage analog signals with the low-pass filter circuit, transmitting the handled current and voltage analog signals to the frequency lock phase lock sampling module, the current and voltage digital signal which is exported from the frequency lock phase lock are used to the malfunction startup module to start the malfunction, it is used for cable ANN model training module to train the cable ANN model , it is used for cable malfunction distance measurement calculating module to calculate the distance of the power cable malfunction, ascertaining the location of the power cable malfunction accurately.