In order to study the effect of the refractive index of waterborne polyurethane onthe gloss of coating film，aqueous polyurethane with high refractive index was synthesized by thereaction of polyether polyol，diisocyanate and dimethylol propionic acid with common sulfur-containing small molecule dihydric alcohol as chain extender and DMF as catalyst. The particlesize of the dispersion，the transmittance，refraction，gloss，mechanical and thermal properties of the film were analyzed by laser particle size meter，UV-visible spectrophotometer，Abbe refraction meter，electronic universal material testing machine and thermogravimetric analyzer.The effects of the types and contents of sulfur-containing monomers on the refractive indexand Abbe number of the films，especially the effects of the amount of sulfur-containingmonomers on the mechanical properties of the films，the thermal stability of the films，and the optical properties such as light transmittance and gloss of the films，were investigated. Theresults showed that the introduction of sulfur-containing monomers improved the refractive index ofthe waterborne polyurethane coating film and exhibited excellent transmittance and gloss.