Abstract: A positioning method based on the comparison of pulse signal transmission characteristics to address the problem of defect localization in metal sheath grounding circuit of high-voltage cable was proposed. Firstly, based on transmission line theory and considering factors affecting pulse signal attenuation such as skin effect and impedance mutation, a quantitative analysis model for defects in cable sheath grounding circuit was established. Transmission mechanism of pulse signals in cable grounding circuit was revealed, and corresponding defect detection methods and dual current transformer segmentation positioning methods were proposed. Secondly, a defect localization simulation model was constructed using PSCAD electromagnetic simulation software to obtain time-domain waveform characteristics of double exponential pulse signals under different defect types. Through correlation analysis between defects and features, the first peak amplitude was determined as the key criterion for defect detection. Finally, defect simulation and localization experiments were conducted on 110 kV high-voltage cable lines. Based on experimental results, a fitting formula for defect localization was established to accurately identify and locate defects in cable sheath grounding circuit, verifying effectiveness of the proposed method and providing a technical basis for online condition monitoring, abnormal warning, and intelligent operation and maintenance of cable sheath grounding systems.