Solar-driven conversion of CO2 to value-added chemical fuels has been regarded as a promising strategy for solving the climate problem and energy crisis. To realize this goal, it is vital to design photocatalysts with abundant catalytic active sites and excellent charge separation efficiency. Here, perovskite nanocrystals (CsPbBr3) were anchored on two-dimensional molybdenum nitride (MoN) using an in-situ growth method, forming a new and effective 0D/2D CsPbBr3@MoN (CPB@MoN) nanoheterosturcture with close contact interface for CO2 photoreduction. The introduction of MoN, acting as a charge transfer channel, could quickly trap the photoinduced charge from CsPbBr3 and provide abundant catalytic sites for CO2 photocatalytic reactions. For optimized CsPbBr3@MoN composites, the CO yield was 13.86μmol/gh−1 without any sacrificial reagent, which was a 4.5-fold enhancement of the pure CsPbBr3. Further, in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) revealed the catalytic mechanism for the CO2 photoreduction process. This work provides a new platform for constructing superior perovskite/MoN-based photocatalysts for photocatalytic CO2 reduction.