Since fault line selection cannot be performed reliably and accurately when a high-resistance single-phase grounding fault occurs in a resonant grounded distribution network system, a scheme based on the difference of transient high-frequency current waveform is proposed. Analyzing the zero-sequence current characteristics of a single-phase grounding fault system in a resonant grounding system, there are still significant differences in the waveforms of the fifth and seventh components of the transient current between the sound line and the fault line. The Hausdorff distance algorithm is used to compare the waveform differences of the main high-frequency components of the transient current between lines for fault line selection. Through the normalization of the transient current component of each line, the fault line selection criterion of the Hausdorff distance parameter of that component is constructed, and an implementation scheme is designed. The correctness and effectiveness of the proposed line selection scheme are verified by Matlab simulation and test recording, especially for a high-resistance single-phase grounding fault in a distribution network. This work is supported by the Key Research and Development Project of Shaanxi Province (No. 2020GY-169).