The design and application of single-atom catalysts have gained significant attention in photocatalysis. However, precisely and firmly anchoring single atoms on substrate surfaces remains a challenge. This study employs an innovative silane coupling agent grafting strategy to precisely and stably anchor Cu single-atoms on the substrate. Scanning ransmission lectron microscopy (STEM) and X-ray absorption fine structure spectroscopy (XAFS) confirm the successful loading of Cu single-atoms. Photoelectric tests show that the stable channel formed by the carbon chain effectively enhances carrier separation and transport efficiency between Cu and the substrate. Density functional theory (DFT) calculations indicate that the adsorption energy barrier of the intermediate product is reduced by 0.106 eV, improving the reaction kinetics. After grafting with the silane coupling agent, the performance of Cu single-atom-loaded materials is further enhanced by 12.16 times. The strong anchoring prevents Cu single-atom detachment and aggregation during photocatalysis, while excess charge carriers produced by Cu atoms are efficiently transferred to the substrate for reaction. Compared to traditional Cu single-atom supported catalysts, the grafted samples in this study demonstrate superior performance and stability in photocatalytic reduction reactions. This approach provides a reliable and innovative pathway for the directional and stable production of single-atom catalysts.