Cu-TiO2/g-C3N4 noble-metal-free ternary hybrid catalyst was fabricated for visible light photocatalytic conversion of CO2 to methane. It was found that the photocatalytic performance of the catalyst is strongly dependent on its Cu dispersion and content. The NaBH4 in-situ reduction of the catalyst could generate desirable Cu coating and heterojunction construction. Furthermore, the optimized Cu content is 2.5 wt%, which exhibited the excellent production rates of CH4 (23.88 mu mol g(-1) h(-1)) and H-2 (2.27 mu mol g(-1) h(-1)).