A method of chemical modification of rubber bv alkyds comprising the steps of prepartion of alkyd and blending the prepared alkyd with natural rubber or epoxidized rubber either before or after rubber compounding. The alkyd is prepared by polymerization of natural oil, polyfunctional acid and polvol. The polymerization may further comprises unsaturated acids to further enhance the performance of alkyd in modification of rubber. The present invention further provides an 0 alkvd modified rubber composition obtained thereof. The modifed rubber is enhwiced with specific properties for different application through variation of chemical structure and composition of alkyd, and the proportion of alkyd relative to the rubber.