There　are　three　big　defects　in　the　existing　optical　voltage　transducers　(OVTs).　The　first　one　is　that　the　measurement　mode　had　optical　power　dependence,　the　second　one　is　a　non-linear　measurement,　and　the　third　one　is　that　the　inherent　half-wave　voltage　of　the　crystal　limits　the　measurement　range　and　measurement　sensitivity.　These　defects　severely　impair　the　reliability　and　accuracy　of　OVT＇s　long-　term　operation.　The　idea　to　solve　the　above　problem　is　to　achieve　direct　linear　measurement　of　the　electro-optic　phase　delay.　To　this　end,　this　paper　presented　a　linear　OVT　based　on　a　strip　aluminum　polarization　grating　(SAPG).　It　was　a　synchronous　translation　that　directly　converts　the　electro-optical　phase　delay　into　a　spot　image,　and　used　a　position-sensitive　detector　to　position　the　spot　to　achieve　linear　measurement　of　voltage.　This　method　overcomes　the　above　three　principle　defects,　and　improves　temperature　drift.　The　measurement　range　of　the　electro-optical　phase　delay　reached　±100　degrees,　and　the　measurement　accuracy　reached　0.2　level.　©　2021　Chin.　Soc.　for　Elec.　Eng.