Abstract: Air-drying-DCPD-type unsaturated polyester resin prepared by using modified hydrolysis addition method was proposed in the paper. By virtue of the theoretical analysis of IR and NMR,the mechanism of synthesis reaction and the optimal technological conditions were investigated. As a result,development was completed on the air drying unsaturated polyester resins,which have excellent properties such as shorter gelation time,higher cured velocity,higher mechanical strength,greater hardness,and better thermal and chemical resistances.