Partially esterification of rosin with glycerol and addition reaction of rosin glycerol ester with epoxy ethane were investigated.The suitable reaction conditions were obtained:the ratio of rosin to glycerol for esterification was 1∶2(mol/mol),reaction temperature of esterification was 260~270 ℃,amount of catalyst of ZnO for esterification was 0.05% (based on rosin(g)),reaction time of esterification was 4.5 h.Amount of catalyst KOH for addition of rosin ester with epoxy ethane was 0.6% (based on rosin glycerol ester(g)),reaction temperature of addition was 150 ℃.Surface physicochemical properties of the products were measured.The results showed that surface tension (δ) varied from 3.29×10-2 to 3.83×10-2 N/m,critical micelle concentration(CMC) from 2.2×10-4 to 5.2×10-4 mol/L,lime soap dispersing power(LSDP) from 4.2% to 18.5%,emulsifying power(EP, with turpentine) from 74 s to 190 s,cloud point from 17 ℃ to 81 ℃.The relations between surface physicochemical properties of the products and polymerization degree of ethylene oxide(EO) were first studied systematically.With the increasing of polymerization degree(n) of EO,the surface activity was rising firstly,and then tending towards stability or dropping a little,the application properties,such as EP and LSDP,became better with increasing of n,and reached balance when n=10.