Carbon-doped nano-Bi2WO6 photocatalysts with different carbon contents were successfully prepared by a facile hydrothermal method at 433 K, and characterized by XRD, BET, XPS, TEM, HR-TEM, SEM, EDX, photoluminescence (PL) and UV-vis spectroscopy. The photocatalytic activity of C-Bi2WO6 was evaluated from the analysis of the photodegradation of methylene blue (MB). The results show that the C-Bi2WO6 photocatalysts exhibit an orthorhombic Bi2WO6 phase. With the increase of carbon content, the absorption intensity of C-Bi2WO6 samples increases in the 410-650 nm region and the absorption edge has a little shift to long wavelength. Compared with reference C-TiO2 or pure Bi2WO6, 0.47 % C-Bi2WO6 shows obviously higher UV and visible light photocatalytic activities. The remarkably enhanced photocatalytic activities can be mainly attributed to the fact that the proper carbon doped into nano-Bi2WO6 increases its BET surface area, enhances the absorption in the 410-650 nm region, improves the separation efficiency of photogenerated electrons and holes, and enhances the formation rate of OH on its surface.