The synthesis of flexible isocyanate prepolymer,the selection of flexible fluorocarbon resin,the preparation of flexible fluorocarbon topcoat and the construction process were studied.The developed flexible fluorocarbon topcoat has excellent physical and mechanical properties and UV aging resistance.Under UV radiation environment,this topcoat can still maintain good tensile strength and break elongation,ensuring the effective operation of the entire protective layer.The use of epoxy sealer,flexible polyurethane intermediate paint and flexible fluorocarbon topcoat protection system can solve the frost heave,cracking,spalling and other diseases of the concrete beams and piers of the railway with severe UV radiation and severe freeze-thaw damage.Three protection layers can improve durability and extend service life of concrete bridges.