A preparation method of a waterproof and electric breakdown-resistant coating, characterized in that the method comprises the following steps: placing a base material in a plasma reaction chamber, vacuuming the reaction chamber continuously to a vacuum degree of 10-200 millitorrs, and feeding inert gas or nitrogen; feeding a monomer vapour until the vacuum degree is 30-300 millitorrs, starting plasma discharge to conduct chemical vapor deposition, and preparing a waterproof and electric breakdown-resistant coating on the surface of the base material, wherein the component of the monomer vapour is: a mixture of at least one monofunctional unsaturated fluorocarbon resin and at least one polyfunctional unsaturated hydrocarbon derivative, and the mass percent of the polyfunctional unsaturated hydrocarbon derivative in the monomer vapour is 30-50%; stopping plasma discharge, stopping feeding the monomer vapour, vacuuming continuously to maintain a vacuum degree of 10-200 millitorrs in the reaction chamber, feeding air after 1-5 min to make the reaction chamber reach atmospheric pressure, and then taking out the base material; wherein the monofunctional unsaturated fluorocarbon resin includes: 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl methacrylate, 2-(perfluorodecyl)ethyl methacrylate, 2-(perfluorohexyl)ethyl methacrylate, 1,1,2,2-Tetrahydroperfluorotetradecyl acrylate, 1H,1H,2H,2H-Heptadecafluorodecyl acrylate, 1H,1H,2H,2H-Perfluorooctylacrylate, 2-(Perfluorobutyl)ethyl acrylate, (2H-perfluoropropyl)-2-acrylate, (perfluorocyclohexyl)methyl acrylate, 1-propyne,3,3,3-trifluoro-, 1-ethynyl-3,5-difluorobenzene or 4-ethynyl-trifluorotoluene; and the polyfunctional unsaturated hydrocarbon derivative includes: ethoxylated trimethylolpropane triacrylate, tripropylene glycol diacrylate, divinylbenzene, poly(ethylene glycol) diacrylate, 1,6-hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol divinyl ether or neopentyl glycol diacrylate. placing a base material in a plasma reaction chamber, vacuuming the reaction chamber continuously to a vacuum degree of 10-200 millitorrs, and feeding inert gas or nitrogen; feeding a monomer vapour until the vacuum degree is 30-300 millitorrs, starting plasma discharge to conduct chemical vapor deposition, and preparing a waterproof and electric breakdown-resistant coating on the surface of the base material, wherein the component of the monomer vapour is: a mixture of at least one monofunctional unsaturated fluorocarbon resin and at least one polyfunctional unsaturated hydrocarbon derivative, and the mass percent of the polyfunctional unsaturated hydrocarbon derivative in the monomer vapour is 30-50%; stopping plasma discharge, stopping feeding the monomer vapour, vacuuming continuously to maintain a vacuum degree of 10-200 millitorrs in the reaction chamber, feeding air after 1-5 min to make the reaction chamber reach atmospheric pressure, and then taking out the base material; wherein 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl methacrylate, 2-(perfluorodecyl)ethyl methacrylate, 2-(perfluorohexyl)ethyl methacrylate, 1,1,2,2-Tetrahydroperfluorotetradecyl acrylate, 1H,1H,2H,2H-Heptadecafluorodecyl acrylate, 1H,1H,2H,2H-Perfluorooctylacrylate, 2-(Perfluorobutyl)ethyl acrylate, (2H-perfluoropropyl)-2-acrylate, (perfluorocyclohexyl)methyl acrylate, 1-propyne,3,3,3-trifluoro-, 1-ethynyl-3,5-difluorobenzene or 4-ethynyl-trifluorotoluene; and the polyfunctional unsaturated hydrocarbon derivative includes: ethoxylated trimethylolpropane triacrylate, tripropylene glycol diacrylate, divinylbenzene, poly(ethylene glycol) diacrylate, 1,6-hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol divinyl ether or neopentyl glycol diacrylate.