Ba2TiGe2O8　(BTG)　shows　excellent　second-order　nonlinearity　and　electro-optical　effects.　However,　it　is　difficult　to　grow　a　perfect　BTG　single　crystal,　and　the　accurate　refractive　indexes　of　this　crystal　are　unavailable　at　present.　In　this　paper,　a　sizeable　single　BTG　crystal　with　high　quality　was　grown　by　Czochraski　(CZ)　method.　SEM　and　EDS　analyses　of　crystal　defect　indicate　that　the　volatilization　of　GeO2　and　the　obvious　supercooling　feature　of　BIG　melt　were　the　main　inducements　of　inclusion　defects.　The　accurate　refractive　indexes　were　measured　by　the　self-collimating　method.　The　birefringence　and　SHG　results　show　that　the　angle　phase　matching　of　SHG　at　1064　nm　hardly　be　achieved　in　this　crystal.　Nevertheless,　the　effective　frequency-doubled　laser　output　may　be　achieved　by　using　the　technique　of　periodic　polarization　reversal　for　quasi　phase　matching.　In　view　of　the　high　optical　transmittance　and　the　huge　nonlinear　optical　coefficients,　BIG　crystal　may　be　a　good　candidate　material　for　nonlinear　optical　devices　and　electro-optical　devices.　(C)　2015　Elsevier　B.V.　All　rights　reserved.