The　three　kinds　of　well-known　bismuth　molybdates　α-Bi2Mo3O12,　β-Bi2Mo2O9,　and　γ-Bi2MoO6　have　been　prepared　employing　mild　hydrothermal　methods.　By　tuning　the　Bi/Mo　ratio　and　pH　values,　controlling　formation　of　bismuth　molybdates　can　be　achieved.　Low　pH　and　high　concentration　of　molybdenum　lead　to　the　formation　of　α-Bi2Mo3O12.　High　pH　and　high　concentration　of　bismuth　lead　to　the　formation　of　γ-Bi2MoO6.　The　pure　form　of　the　β-phase　can　be　prepared　by　calcining　the　hydrothermal　product　at　560　°C.　Photophysical　and　photocatalytic　studies　show　that　Aurivillius　structure　γ-Bi2MoO6　shows　an　intense　absorption　band　in　the　visible　light　region　and　better　photocatalytic　activity　than　α-Bi2Mo3O12　and　β-Bi2Mo2O9　under　visible　light　irradiation.　The　factors　that　result　in　different　photocatalytic　activities　for　three　kinds　of　photocatalysts　are　discussed.　©　2009　Elsevier　B.V.　All　rights　reserved.