A method for moistureproof coating of an electrical product, which comprises applying an organic solution of a polyfluoroalkyl group-containing polymer dissolved in a non-combustible low boiling point organic solvent, to a surface of an electrical product, and drying it by evaporating the low boiling point organic solvent, to form a coating layer of the polyfluoroalkyl group-containing polymer on the surface of the electrical product, wherein said polyfluoroalkyl group-containing polymer is a copolymer of a polymerizable compound having a polyfluoroalkyl group with other polymerizable compound, and the copolymer has a glass transition temperature of not higher than 60.degree. C.