Cationic fluorinated waterborne polyurethane (WCFPU) emulsion containing perfluoroalkyl side chain was prepared by the reaction of isophorone isocyanate (IPDI), polyether polyol (PTMG1000), N - methyldiethanolamine (MDEA), 1,4 - butanediol (BDO), trimethylol propane (TMP) and modified by 2-(perfluorooctyl) ethyl alcohol (FEOH). The structure of the polymer and performance of the film were characterized by fourier transform infared spectrometer (IR), thermogravimetric analysis (TGA), and the cationic fluorinated waterborne polyurethane was used as paper water and oil-resistant agent, the contact angle of water and liquid paraffin and the fiber morphology of sized paper surface were also investigated. The results showed that during the process of casting films, the fluorinated group stretched on the interface exterior of the air and the polymer, which could beneficial to form low energy surface and protect the inner molecule of the polymer effectively; and the films were provided with excellent heat resistance property. And the excellent water and oil-resistant property was reached when the concentration was 0.3 wt%, the contact angle of water was 134.7°,the contact angle of liquid paraffin was 119.2°.