Taking waterborne polyurethane dispersion lotion as the research object,based on the relationship between the molecular structure of polyurethane and its fast drying properties,a polyurethane particle emulsion containing carboxyl functional groups was synthesized and characterized.The fast drying type JS waterproof coating is made,and its drying time can reach 1.58 h,which is faster than the commercially available type Ⅲ JS waterproof coating.The fast drying mechanism of JS waterproof coating was proposed.