Solar thermochemical cycle has emerged as a promising clean energy technology that enables the splitting of water for solar fuel production. However, conventional two-step thermochemical cycles using single-metal oxides require high operating temperature above 1000 °C, especially for the reduction step. Typical solar thermal systems struggle to meet such high temperature requirements, making it vital for reducing the operating temperature. To find a solution enabling lower temperature requirement, we proposed a photo-thermochemical reduction (PTR) strategy, which employs light illumination as assistance, combining both thermally-induced and photo-induced effect for more generation of oxygen vacancies (Vos), with the oxygen carrier copper ferrite (CuFe2O4). Experimental studies were performed in a specially-designed photo-thermogravimetric analyser (photo-TGA) that directly measures the weight change of solid reactants under direct light illumination. The results indicate that the photo-thermochemical reaction achieves a decrease of nearly 40 °C in temperature requirement, giving a higher oxygen release of 21% compared to that driven by pure thermal heating at 800 °C. We also measured an increase of 0.09 in the non-stoichiometry parameter δ in photo-TGA. Additionally, we observed oxygen release increases distinctly with light intensity of incident illumination. From the viewpoint of spectral ranges, ultraviolet and visible light illumination give the primary boost to the generation of photo-induced oxygen vacancies. These results demonstrated the effective assistance of concentrated solar energy to enhance two-step thermochemical cycle for solar fuel production at lower temperature.