Abstract: Photocatalytic carbon dioxide (CO₂) reduction into valuable fuels is one of the most promising ways to mitigate the greenhouse effect and combat the energy crisis. However, the reaction mechanism is in urgent need of further in-depth study through advanced characterization. Synchrotron radiation X-ray absorption fine structure (XAFS) provides atomic-scale insights into coordination and electronic structural of photocatalysts. In-situ XAFS enables real-time monitoring of structural changes and catalytic activity of photocatalysts. Furthermore, X-ray emission spectroscopy (XES) can investigate the dynamics of photogenerated electrons and elucidate the potential mechanism of photocatalytic CO₂ reduction. In this review, the research progress of synchrotron radiation in photocatalytic reduction of CO₂ was summarized. The synchrotron radiation-based X-ray absorption spectroscopy (SR-XAS), Fourier transform infrared spectroscopy, In-situ near-atmospheric pressure X-ray photoelectron spectroscopy were discussed. Finally, the opportunity and challenge of synchrotron radiation in photocatalytic reduction of CO₂ were presented.