The curing reaction rate of waterborne clear coat has a great influence on thewaterborne 3C1B system applied by“wet on wet”process. The curing reaction rate ofwaterborne clear coat is mainly controlled by melamine resin.Three different types of melamineresins were characterized by FT-IR and their molecular structures were analyzed.The saidmelamine resins were used as the crosslinking agent to prepare the waterborne clear coat，and the effect of the melamine resins on the curing reaction rate of the waterborne clear coat wasinvestigated by measuring the shear storage modulus of the clear coat during curing withrotational rheometer.The film properties of the prepared waterborne clear coat with waterborneprimer and basecoat in 3C1B process were compared，and the effect of melamine resins on the film properties was analyzed.The results showed that the curing rate of waterborne clear coatwith methylated / butylated melamine as crosslinker was suitable for 3C1B system，and the properties of the prepared paint film were the best.