In order to solve the poor effect of demulsifier in Karamay oil field, acrylic acid esterification and polymerization with the base material of polyamine block polyether to improve the dehydration effect, the modified demulsifier was synthesized under the optimum conditions of premixing temperature at 120 ℃, esterification temperature at 85 ℃, esterification time for 8 h,polymerization temperature at 85 ℃, polymerization time for 6 h, with mechanical stirring. The modified demulsifier was characterized by i...