Described herein is a cardanol-derivatives modified polymer obtained from a reaction of epoxy groups in a cardanol-derivative compound and carboxyl groups in a carboxyl-functional polymer, where the cardanol-derivative compound is the reaction product of cardanol-derivatives modified with haloalkylene oxide having a carbon number of from 3 to 10. Also described herein is a process of preparing the cardanol-derivatives modified polymer, a method of using the cardanol-derivatives modified polymer in automotive coatings, and the obtained coating composition thereof.