Abstract: This paper presents a method of single-phase grounding fault line selection based on variational mode decomposition of zero sequence current signal, aiming to solve the problem of low accuracy and poor reliability of single line selection criterion when single-phase grounding fault occurs in 10 kV power supply and distribution system. In this method, the zero sequence current signal is decomposed, and the fault line is identified according to the double criterion of high frequency component energy and power frequency component initial phase difference. The model of 10 kV power supply system is built by PSCAD, and the results of the method in different fault conditions are verified by simulation. The results show that this method is not affected by fault location, fault ground resistance and initial phase angle, and has high sensitivity, and can accurately and reliably distinguish fault lines.