A　new　type　of　optical　voltage　sensor　(OVS)　based　on　conoscopic　interference　is　proposed,　and　its　performance　is　simulated　with　the　aid　of　polarized　optical　theory.　Due　to　the　polarized　light　convergent　interference,　the　electro-optical　phase　change　is　converted　to　the　real　time　rotation　of　image.　This　new　OVS　has　a　wide　phase　measurement　range　extended　to　180　degree.　Different　from　normal　intensity　measurement　mode,　OVS　based　on　conoscopic　interference　measure　the　electro-optical　phase　linearly,　and　measured　signal　is　unrelated　to　the　absolute　light　intensity.