The invention discloses nanofiber heavy-duty anti-corrosive coating, a preparation method and a spraying method of the nanofiber heavy-duty anti-corrosive coating. The anti-corrosive coating comprises components C, A and B by mass ratio. The preparation method comprises the steps of preparing mixed solvent C, dissolving resin and preparing resin solution, pouring the dissolved resin solution into a ball mill for stirring and refluxing, then pouring the component A into the ball mill, uniformly stirring with a glass rod initially, performing ball milling and filtering, pouring the component B into the ball mill, uniformly stirring, adding the component B into the component A, and then uniformly stirring to obtain the nanofiber heavy-duty anti-corrosive coating. The spraying method comprises the steps of cleaning up the surface of an object to be sprayed, uniformly spraying the coating onto the surface of the object to be sprayed with a spray gun, and drying or naturally drying the sprayed surface. The nanofiber heavy-duty anti-corrosive coating has super-normal acid resistant, alkali resistant, salt resistant, water vapor corrosion resistant and harmful substances corrosion resistant capabilities, is non toxic, harmless, tasteless and environmentally friendly, and is applicable to the fields of ocean vessels, submarines, ocean engineering, drilling platforms, wharfs, water conservancy facilities, petrochemical equipment, bridge buildings, concrete facilities and the like.