In　this　study,　large　single-crystal　anatase　TiO2　bipyramids　were　first　successfully　synthesized　using　a　simple　hydrothermal　route.　The　synthesized　bipyramids　were　characterized　by　XRD,　SEM　and　TEM　measurements,　and　found　that　these　bipyramids　are　highly　crystalline　anatase　TiO2　with　a　size　up　to　3.6　μm　between　the　two　ends.　On　the　other　hand,　it　was　also　found　that　the　size　and　shape　of　bipyramids　were　significantly　influenced　by　the　pH　value.　Based　on　a　series　of　experimental　results,　a　possible　model　for　the　process　of　dissolving-coalescing-growing,　has　been　proposed　for　the　formation　of　large　anatase　TiO2　bipyramids.　©　2009　Elsevier　B.V.　All　rights　reserved.