Porous polystyrene divinylbenzene was prepared by suspension polymerization, and then sulfonie acid ion exchange resin was obtained by sulfonated porous polystyrene divinylbenzene. The resin’s morphology and degree of sulfonation were characterized with SEM/EDS, BET, IR respectively. Esterification of waste frying oils with acid value of 63.0mg/g was studied using cation exchange resin as catalyst to investigate its catalytic activity. 40.0% dosage of porogen was preferred when the polymerization conditions were 360r/min, 1.0% dispersant, 1.0% initiator, 75℃ for 4h and the heat to 85℃ for 6h,while the sulfonation conditions were 1.0mL/g dichloroethane, 5.0mL/g sulfuric acid, 70℃ sulfonated for 1h and the heat to 80~85℃ for 3h, the optimum swelling time was 1h, and the concentration of sulfuric acid was 98%. The maximum exchange capacity of the cation exchange resin W2 was 5.2mmol/g in that condition. When the esterification was performed in the condition of 40.0% methanol, 10.0% W2, 70℃ stirring for 1.5h, the crushing rate of W2 was only 10.0% and the conversion rate of FFA reached to 86.8%. W2 is better than commercially available cation exchange resin PC101, and could be reused for 5 times.