This disclosure discloses a radiative cooling optical filter, comprising a substrate. One side of the substrate is polished, and the rough side of the substrate is provided with a metal reflective layer. The polished side of the substrate is subsequently provided with the intermediate layers and a top layer. The intermediate layer comprises alternatingly arranged layers A and layers B. The thickness of each layer A and layer B is 50-400 nm. The material of the layer A is silicon dioxide or aluminum oxide, and the material of the layer B is titanium dioxide, silicon nitride or silicon carbide. The material of the top layer is ytterbium fluoride, yttrium fluoride or zinc sulfide. The intermediate layer and the top layer jointly constitute a multi-resonant absorption enhancer in the atmospheric transparent window.