Microspheric　and　lamellar　BiVO4　powders　were　selectively　prepared　through　a　hydrothermal　process　by　using　cetyltrimethylammonium　bromide　(CTAB)　as　a　template-directing　reagent.　The　as-prepared　BiVO4　powders　were　characterized　by　X-ray　diffraction,　electron　microscopy,　nitrogen　adsorption-desorption　experimentation,　Fourier　transform　infrared　spectrometry,　and　UV-vis　diffuse　reflectance　spectroscopy.　Experimental　results　indicate　that　microspheric　BiVO4　with　particle　sizes　in　the　range　of　7∼12　μm　can　be　derived　from　a　relatively　low　hydrothermal　temperature　(≤　160　°C)　and　possess　a　mixed　crystal　consisting　of　tetragonal　and　monoclinic　phases,　whereas　lamellar　BiVO4　with　a　pure　monoclinic　phase　can　be　obtained　at　a　higher　hydrothermal　temperature　(200　°C).　Their　photocatalytic　activities　for　O2　evolution　were　investigated　by　using　Fe(NO　3)3　as　a　sacrificial　reagent　under　visible-light　irradiation,　and　the　lamellar　BiVO4　shows　a　better　photoactivity　than　the　microspheric　product　due　to　its　pure　monoclinic　crystal　phase.　Moreover,　the　effects　of　CTAB　content　on　the　morphologies　and　crystal　phases　of　the　obtained　products　were　also　discussed.　It　was　found　that　the　addition　of　CTAB　can　adjust　the　morphologies　of　BiVO4　and　obstruct　the　crystal　phase　transformation　from　the　mixed　crystal　to　pure　monoclinic　BiVO4　during　the　hydrothermal　process.　©　2009　American　Chemical　Society.