The invention discloses an RFL treatment agent and application thereof. The RFL treatment agent at least comprises vinylpyridine-styrene-butadiene copolymer latex, halogenated polymer latex and water-soluble condensate of resorcinol and formaldehyde; and by taking the solid content of the vinylpyridine-styrene-butadiene copolymer latex as 100 portions, the solid content of the halogenated polymerlatex is 36 to 45 portions and the solid content of the water-soluble condensate of resorcinol and formaldehyde is 4 to 12 portions. When the RFL treatment agent is used for preparing rubber product reinforcing glass cords, the prepared rubber product reinforcing glass cords have good heat and water resistance, and the durability and water resistance of various rubber products such as rubber conveyor belts giving priority to synchronous belts, rubber tyres and the like which are prepared from the glass cords serving as a reinforcing material are greatly improved when the rubber products are used in the environment of high temperature and high humidity.