The invention discloses a long-acting protective liquid self-secreting super-lubricity coating and a preparation method thereof, and belongs to the anti-corrosion, anti-fouling and anti-icing fields and the like. A coating body is an elastic porous film layer and is divided into a bottom layer, an upper layer and a surface layer. The bottom layer is of a large pore structure, the porosity is as high as 60%-95%, the pore diameter ranges from 100 microns to 2000 microns, and the oil storage amount is increased; the upper layer pore diameter ranges from 10 nm to 100 microns, the thickness rangesfrom 50 microns to 1000 microns, oil is prevented from being lost too fast, and the secretion process is controlled; and the surface layer is of a micro-nano-level convex structure, the roughness ranges from 10 nm to 50 microns, and the lyophobic and oil storage effects are achieved. Lubricating oil is stored in the porous structure, when surface oil dries, the oil can be gradually diffused to thesurface layer through upper-layer small holes to form a liquid protective oil film. Corrosion inhibitors, bactericides and the like added into the lubricating oil are released along with the oil, andthe protective function of the coating is enhanced. When environmental water flow impact, external force extrusion, friction and the like lead to losing of the surface oil film, the external force effect will also promote deformation of the elastic porous structure to secrete oil, it keeps that a stable oil layer is formed on the surface, and the service life of the coating is significantly prolonged.