A novel visible-light-driven photocatalyst with formula of Bi(2)W((1-x))NbxO(6-y) was synthesized by using a facile hydrothermal method. The effects of acceptor dopant Nb5+ on the properties of Bi2WO6 (BWO) were systematically investigated. Results showed that a moderate amount of acceptor dopant Nb5+ ions could enter into the W-sites of BWO lattice and tailor the morphology of BWO from the 3D hierarchical microspheres to 2D nanosheets. The 2D nanosheet morphology with about 7.5 nm in thickness provides shorter diffusion distance of charge carries and the oxygen vacancies produced by the acceptor dopant Nb5+ have advantage of separating the photo-induced charge carriers, and thus resulted in enhanced photocatalytic properties. The composition with x = 0.02 showed optimal photocatalytic performance, which could fully degrade RhB in an aqueous solution within 60 min and the apparent rate constant, k, was estimated to be 0.0509 min(-1), approximately 10.2 times greater than that of the BWO-SSR (prepared by solid state reaction method) sample and 3.9 times greater than that of the pure BWO (prepared by hydrothermal method). Importantly, this kind of catalyst exhibited good cycling performance, and could degrade 92% of the RhB in an aqueous solution within 60 min after 4 cycles, making it a promising visible-light photocatalyst for the environmental remediation applications.