Photocatalysis technology to convert CO₂ into fuels is considered as one promising strategy to mitigate the greenhouse effect and energy crisis. Herein, the Z-scheme Ag/UiO-66@g-C₃N₄ (AUiO@CN) composites exhibit an improved CO₂ photoreduction activity owing to the increased specific surface area, strong redox capacity, rapid separation of photoinduced h⁺/e⁻ pairs and fast transfer of e⁻ at the interface. As a result, CH₃OH and CO evolution rates of AUiO@CN composite are roughly 3.09 and 2.40 times higher than those of g-C₃N₄, respectively. The Quantum yield (QY) of CO and CH3OH for AUiO@CN are 0.0217 % and 0.0986 %. The ESR characterization and a series of electrochemical results confirmed the Ag NPs acted as e⁻ mediator, which could promote the photogenerated charge separation and transport and CO₂ reduction ability. This work not only provides a simple photo-deposition assisted grinding calcination method to prepare ternary composites, but also shows that the prepared ternary heterojunction photocatalyst can realize an efficient photocatalytic CO₂ conversion to methanol and CO.