N-doped TiO2/reduced graphene oxide (N-TiO2/RGO) composites were prepared by a hydrothermal method. Characterization and photocatalytic tests showed that the N-TiO2/RGO composites were more efficient for degrading effluents in comparison with the pure TiO2 powders and the N-doped TiO2 powders. The photocatalytic performance of the composites was enhanced with the increase of the reduced graphene oxides' content, whose degradation rate constant was higher than that of N-TiO2 under simulated sunlight irradiation. After five successive cycles, 50% N-TiO2/RGO still exhibited high activity, which indicates that the composites are stable under irradiation. An innovative strategy for the exploration of advanced photocatalysts in wastewater treatment is provided.