TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The vegetable oil includes 0.8-1.5 wt.% of unsaturated carboxylic acid and 0-10 wt.% of epoxy resin modified epoxy vegetable oil, where the unsaturated carboxylic acid is acrylic acid, acrylic anhydride, alphamethacrylic acid, beta -methacrylic acid, methyl acrylic anhydride, 2-acrylic acid, 2-aminogroup acrylic acid, alpha -phenyl acrylic acid, beta -phenyl acrylate, p-benzene crylic acid, hydroxy phenyl acrylate, 4-hydroxy-3-methoxycinnamic acid, maleic acid, fumaric acid, maleic anhydride or glutaconic anhydride, the epoxy resin is bisphenol A type epoxy resin, bisphenol F-type epoxy resin, bisphenol S-type epoxy resin, polyoxyethylene sub-alkyl-glycol, glycidol ether epoxy resin, ethylene oxidic ester epoxy resin, glycidyl paminophenol, triglycidyl isocyanurate, dicyclopentadiene, dicyclopentadiene dioxide ether or epoxidized polybutadiene, and the vegetable oil is soybean oil, cotton seed oil, rape seed oil, sunflower seed oil, palm oil, linseed oil or rice bran oil. The active diluting agent is methyl acrylate, ethyl acrylate, butyl acrylate, styrene, methyl methacrylate, hydroxyethyl methacrylate, 2-ethyl acrylate, phenoxy ethyl acrylate, ethoxy ethyl acrylate, ethyl acrylic ester, lauric acid ester, stearic acid, isodecyl acrylate, lauric methacrylate, isobornyl acrylate, isobornyl methacrylate, 1, 6-hexanediol diacrylate, ethoxylated 1,6-diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polyethylene glycol diacrylate, neopentyl glycol diacrylate, 1,4-diacrylate, neopentyl glycol diacrylate, propylene oxide neopentyl glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, diethylene glycol dimethacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxide trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxide trimethylolpropane triacrylate or propoxide glycerin acrylic ester. The photo-initiator is benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin ether, benzoin butyl ether, benzoin methyl ether, benzophenone, diphenyl ethyl ketone, 4-methyl benzophenone, 4-benzophenone, 2, 4-benzophenone, 1-phenyl ketone, 4,4'-bis(dimethylamino)benzophenone, phenoxymethyl, 2,2-dimethoxy-2-hypnone, 2-hydroxy-2-methyl-1-hydroxyphenyl, 2-methyl-1-(4-methylthio-phenyl)-2-morpholinyl-1-acetone, benzoyl peroxide, 4-(N,N-dimethyl amino) ethyl benzoate, 2-isopropyl-thioxanthone or thio propoxy thioxanthone. The photo-curing coating material has a viscosity of 5-500 mPa.S. Preferred Process: The spraying process is performed using a two fluid spray gun or a single fluid spraying gun with the spraying speed of 30 g/minutes, at the spraying pressure of 0.01-0.6 MPa.