The application of covalent organic framework (COF) for photocatalytic CO₂ conversion has received more and more attention. However, it is still a challenge for photocatalytic conversion of CO₂ with atmosphere concentration to high added value hydrocarbons products (C_xH_y) such as CH₄ and C₂H₄. Here, integrating the advantages of micropore structure and single atom catalysis, we introduced single- atom MoN₂ sites into COF to construct Mo-COF materials. The aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF- STEM) confirms that Mo single atom on COF. Mo-COF can reduce CO₂ to C_xH_y under visible light with a selectivity of 42.92% and C₂H₄ product was found for the the first time. In-situ fourier transform infrared spectrometer (In situ FT-IR) and theoretical calculation showed that the introduction of single-atom MoN₂ sites is the key to improving the catalysis performance. It also provides a new idea for converting CO₂ into high added value C_xH_y products.