Bicrystalline dehydrated nanoribbon (DNR) with alternate structure of TiO2(B) and anatase has been prepared by a short-time annealing method. It is photoactive for photocatalytic H-2 evolution from water in the visible region sensitized by a novel heteropoly blue sensitizer. The effects of annealing temperature and time on the DNR phase transformation process have been investigated. These results reveal that the nanocavity structure of TiO2(B) exhibits a narrow band gap and improves its absorbance coefficient in the visible region. The alternate structures of TiO2(B) and anatase improve interfacial electron separation and transfer. Compared with normal phase junction, the smoothing alternate joints in the hand structure of DNR-600-30 provide ail effective route for the movement of holes and electrons, This unique alternate bicrystalline structure has a significant advantage oil its applications in photocatalysis and nanodevices.