Abstract: Spherical polynaphthoxazine resin acid catalyst was prepared and applied to esterification reaction of glacial acetic acid and ethanol.Naphthoxazine precursor was converted into spherical polynaphthoxazine resin in methylsilicone oil by reversed-phase suspension polymerization,then polynaphthoxazine resin acid was generated from the reaction of sulfonation.Thermal stability and surface composition of the catalyst were measured by NETZSCH TG 209 and JSM-6390/LV SEM,respectively.Catalytic activity of the resin acid was evaluated through the esterification reaction of glacial acetic acid and ethanol.The results show that the pyrogenation of spherical polynaphthoxazine resin obtained by reversed-phase suspension polymerization will not take place at 300℃.Catalytic activity of the catalyst obtained from sulfonating spherical polynaphtho-xazine resin at 45℃ is the highest,and there is 4.29 mmol/g of sulfonic groups on the surface of resin.The conversion rate of glacial acetic acid was 77% with the catalyst obtained from sulfonation reaction at 45℃ when the reaction time was 2 h,catalyst dosage was 3% (on glacial acetic acid mass) and mole ratio of ethanol to acetic acid was 2:1.