Photocatalytic CO2 reduction is a promising solution to simultaneously provide renewable chemical fuels and address the greenhouse effect. However, designing practical photocatalysts with advanced architectures remains challenging. Herein, we report the preparation of a novel CdIn2S4/TiO2 binary heterojunction via an in situ solvothermal approach, which exhibits superior photocatalytic activity for sunlight-driven CO2 reduction. The CdIn2S4/TiO2 composites exhibit significantly enhanced photocatalytic performance for CO2 reduction compared to unmodified TiO2. Among them, the 3% CdIn2S4/TiO2 composite has optimal CO and CH4 evolution rates of 18.32 and 1.03 µmol·g−1·h−1, respectively. The yield of CO is 4.7 times higher than that of pristine TiO2. This improved photocatalytic activity of the CdIn2S4/TiO2 heterostructure can be attributed to its large surface area, extended light absorption range and high separation efficiency of photogenerated electron-hole pairs, which are supported by the results of photoluminescence spectroscopy and the photoelectrochemical measurements. Moreover, the photocatalytic mechanism based on the binary CdIn2S4/TiO2 heterojunction is proposed and separation process of photogenerated electron-hole pairs is discussed. In brief, we aim to provide insights into the application of TiO2 in energy conversion processes through the construction of heterogeneous junctions.