Abstract: When single-phase to earth fault occurs in the mine power supply system, the collected signal contains a lot of noise because of the bad underground environment, it’s easy to cause the problem of wrong or missing selection. In order to improve those problems, this paper proposes a single-phase to earth fault line selection method based on EEMD and wavelet threshold denoising. Firstly, EEMD is used to decompose the collected zero sequence current signal. Secondly, the wavelet threshold denoising is used to extract the high frequency imf1 component. Thirdly, the Hilbert transform is used to extract the instantaneous amplitude of the imf1 component after denoising. And finally, the fault line is judged according to the principle of maximum energy proportion. A 35/6kV simulation model of mine power supply system is built by RTDS real-time digital simulation system , the line selection method is verified by fault simulation. The result shows that this method has better accuracy and timeliness in different fault conditions.