Bi2ZnOB2O6(BZBO),　which　belongs　to　the　typical　polar　borate,　has　been　successfully　synthesized　by　a　sintering-hydrothermal　two　steps　method,　and　further　characterized　by　XRD,　TEM　and　HRTEM.　The　UV-Vis　reflectance　spectrum　for　BZBO　was　characterized　in　detail,　and　it　has　indirect　transition　optical　band　gaps　of　3.03　eV.　Density　functional　calculations　revealed　that　the　valence　band　and　conduction　band　of　BZBO　were　composed　of　hybridized　states　of　the　O　2p　and　Bi　6s　or　6p　orbitals.　Photodecomposition　experiments　demonstrated　that　BZBO　exhibits　a　high　activity　to　photodegrade　Rhodamine　B　under　UV　light　irradiation.　Through　the　calculation　of　dipole　moment,　it　can　be　found　that　the　polarization　field　in　BZBO,　which　has　a　negative　c-axis　direction,　can　promote　move　of　photo-induced　electron　to　positive　c-axis　direction　and　photogenerated　hole　to　negative　c-axis　direction.　This　will　greatly　improve　the　separation　of　photo-induced　electron　and　photogenerated　hole　and　then　enhance　the　photocatalytic　activity　of　BZBO.