The　optical　voltage　transducer　(OVT)　based　on　the　Pockels　effect　has　a　perennial　issue　of　the　thermal　stress　linear　birefringence　(TSLB)　in　the　electro-optic　crystal　being　overlapped　with　the　electro-optic　phase　delay,　which　is　difficult　to　be　eliminated　and　seriously　affects　the　measurement　accuracy　and　reliability.　In　this　paper　an　AC　zero　crossing　compensation　method　for　TSLB　is　proposed.　It　is　based　on　that　when　the　steady-state　AC　voltage　crosses　zero　points　the　electric　field　is　zero,　and　the　electro-optic　crystal　does　not　have　any　electro-optic　effect,　so　the　electro-optic　phase　delay　is　zero.　In　this　case,　the　output　of　the　OVT　is　an　additional　phase　delay　caused　by　the　TSLB,　which　can　be　separated　and　compensated　by　the　linear　demodulation　OVT　and　the　AC　zero　crossing　detection　circuit.　The　experimental　results　show　that　in　the　temperature　range　of　-40　degrees　C　to　70　degrees　C,　the　measurement　accuracy　of　the　OVT　after　TSLB　compensation　is　improved　from　0.5　class　to　0.2　class.　This　method　is　helpful　for　the　practicality　of　the　OVT.