In　this　paper,　the　external　injected　pulse　signal＇s　propagation　process　and　choice　in　the　grounding　electrode　lines　of　high-voltage　direct　current　(HVDC)　transmission　system　are　analyzed.　On　this　basis,　a　fault　location　method　for　grounding　electrode　lines　of　HVDC　is　presented　using　the　multi　external　injected　pulse　signal.　This　method　is　used　to　detect　the　running　states　of　the　grounding　electrode　lines　by　the　plus　of　8　\mu　s　periodically.　When　the　line　fault　is　determined,　the　fault　location　is　detected　by　the　plus　signals　of　4　\mu　s　and　2　\mu　s.　Finally,　the　fault　location　result　is　obtained　in　the　form　of　the　average　value.　PSCAD/EMTDC　simulation　results　show　that　the　method　has　high　ranging　accuracy　in　HVDC　transmission　system　in　bipolar　and　monopole　operation　modes.　©　2022　IEEE.