Bi-Si　mesoporous　zeolites　(Bi-Si)　with　different　Si/Bi　ratios　were　synthesized　with　the　hydrothermal　method　which　used　TEOS　as　silica　source,　Bi(NO3)3·5H2O　as　metal　source,　cetyltrimethylammonium　bromide　as　template,　and　the　oxidation　of　styrene　by　hydrogen　peroxide　to　benzaldehyde　catalyzed　by　the　zeolite　prepared　was　investigated.　The　nature　of　the　catalysts　was　discussed　based　on　the　characterization　results　with　nitrogen　adsorption-desorption　(BET),　X-ray　diffraction　(XRD),　scanning　electron　microscopy　(SEM),　Fourier　transform　infrared　spectroscopy　(FTTR),　ultraviolet-visible　spectroscopy　(UV-Vis),　and　thermogravimetric　method　(TG).　Bi-Si　had　high　ordering　structures　of　Mobile　Crystalline　Material-41　and　bismuth　was　highly　dispersed　in　the　mesostructure　framework.　With　the　increase　of　bismuth　content,　the　crystallite　of　Bi-Si　became　disorderly,　and　at　the　same　time　the　value　of　d100　decreased.　Bi-Si　was　found　to　be　catalytically　active　in　the　oxidation　of　styrene　to　benzaldehyde　with　H2O2　as　oxidant　and　methanol　as　solvent.　The　conversion　of　styrene　increased　with　the　increase　of　Bi　content,　while　the　selectivity　of　benzaldehyde　decreased.　The　catalyst　with　Si/Bi　=　22.5　(mole　ratio)　showed　higher　catalytic　activity,　and　the　yield　of　benzaldehyde　reached　14.1%.　The　influence　of　the　ordering　of　mesostructure　and　the　Bi　content　on　the　oxidation　activity　of　Bi-Si　was　also　discussed.