Most　traditional　voltage　transformers　in　transmission　and　distribution　networks　are　installed　inside　the　substations.　Nearly　no　accessible　voltage　information　in　the　real-time　scale　is　available　for　field　engineers　to　carry　out　the　field　measurement　for　the　purposes　of　the　power　quality　inspection　and　the　equipment　maintenance.　In　order　to　offer　an　on-site　and　easy-to-use　solution　for　the　field　measurement,　the　authors　propose　a　novel　electric-field　(EF)　sensor　array　based　technique　for　measuring　the　overhead-line　voltage.　Based　on　the　EFs　measured　by　the　EF　sensor　array　and　the　partially　known　overhead-line　geometry　information　from　utilities,　the　proposed　voltage　algorithm　can　accurately　calculate　each-phase　voltage　without　an　on-site　calibration　before　conducting　the　field　measurement.　The　simulation　results　demonstrate　that　the　authors＇　proposed　technique　with　only　three　EF　sensors　can　accurately　calculate　the　overhead-line　voltages　and　successfully　reconstruct　the　real-time　three-phase　waveforms.　The　experiment　results　verify　the　feasibility　of　the　proposed　voltage　sensor　for　the　overhead-line　voltage　measurement.