The　intrinsic　linear　birefringence　and　its　temperature　characteristic　of　the　BGO　crystal　seriously　restricts　the　development　of　optical　voltage　sensor,　thus　the　study　on　the　intrinsic　linear　birefringence　is　of　great　significance　to　improve　the　performance　of　the　optical　sensors.　An　interference　fringes　method　employing　a　crystal　wedge　was　proposed　in　this　paper,　and　the　measurement　for　the　intrinsic　linear　birefringence　of　the　crystal　inside　the　sensing　head　can　be　realized　by　measuring　the　fringes＇　displacement.　The　theoretical　deduction　of　the　measuring　principle　was　given　taking　Jones　matrix　as　a　mathematical　tool,　the　application　example　and　the　verifying　results　were　also　given,　which　indicates　that　the　intrinsic　linear　birefringence　and　its　temperature　characteristic　can　introduce　an　error　of　about　1%　to　the　voltage　sensor.　Compared　with　the　traditional　intensity　method,　the　measured　results　of　this　method　are　insensitive　to　the　power　fluctuation　of　light　source,　and　there　is　no　adjustment　of　any　optical　components　during　the　whole　experiment,　so　no　additional　error　will　be　induced.　The　measurement　accuracy　is　improved　by　about　one　order　of　magnitude.　©　2016,　Editorial　Board　of　Journal　of　Infrared　and　Laser　Engineering.　All　right　reserved.