The invention discloses a visible photocatalysis functional topcoat with quantum dots and a preparation method of the visible photocatalysis functional topcoat. The visible photocatalysis functional topcoat comprises the following components in percentage by weight: 1-10% of a silicate coating resin, 1-10% of noble metal ion doped titanium dioxide quantum dots, 0.02-2% of silicon nanoparticles, 0-1% of FeOOH nanoparticles, 0.1-1% of a leveling agent, 0.1-1% of a dispersant, 0.1-1% of a thickening agent, 0.1-1% of a defoaming agent and the balance of water. Compared with a conventional photocatalysis coating, the visible photocatalysis functional topcoat with the quantum dots is capable of remarkably improving a photocatalysis effect, continuously and efficiently removing harmful substancessuch as formaldehyde, benzene, ammonia, TVOCs (total volatile organic compounds) and PM2.5 and purifying indoor air environments and outdoor haze elimination, and killing bacteria, viruses, fungi, microorganisms in a broad spectrum, can be used temporarily once being used, and in addition is safe to use.