A　contactless　DC　current　measurement　method　that　can　be　easily　applied　in　the　on-site　environment　for　HVDC　overhead　lines　is　presented.　The　ground-level　magnetic　field　under　the　overhead　line　is　measured　by　a　TMR　sensor　array,　which　is　combined　with　partially　known　overhead　line　geometry　to　estimate　the　current　of　the　overhead　line.　A　space　magnetic　field　model　of　overhead　line　is　built　up　to　verify　the　feasibility　of　the　proposed　method　and　analyze　the　current　measuring　accuracy　of　the　proposed　method　under　the　influence　of　errors　of　unknown　variables　and　TMR　sensors.　Finally,　an　equal　scale　reduction　model　of　the　overhead　line　is　built　up　to　verify　the　feasibility　of　the　proposed　method.　©　2020,　Electric　Power　Automation　Equipment　Press.　All　right　reserved.