Bi2O2CO3/ZnWO4 composite photocatalysts have been successfully synthesized by a mixed calcination method after hydrothermal process. The catalysts were characterized by powder x-ray diffraction, scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, x-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectrum. The results showed that the hierarchical Bi2O2CO3/ZnWO4 nanocomposites were obtained by mixed grinding calcination method and Bi2O2CO3 nanospheres grow on the primary ZnWO4 particles. The Bi2O2CO3/ZnWO4 composites exhibit higher photocatalytic activities compared to pure ZnWO4 and Bi2O2CO3 particles under UV light irradiation. Furthermore, the excellent photocatalytic efficiency of the Bi2O2CO3/ZnWO4 composite was deduced closely related to Bi2O2CO3/ZnWO4 heterojunctions whose presence is generally regarded to be a favorable factor for the separation of photogenerated electrons and holes.