Taking maleic anhydride as acylating agent, hydroxylated soybean phospholipids were acylated. The influences of reaction time, reaction temperature and anhydride dosage on the acylating rate of modified phospholipids were studied. The reaction conditions were optimized by response surface methodology as follows: reaction time 30 min, reaction temperature 55 ℃, and acylating reagent dosage 4%. Under the optimum conditions, the acylating rate was 61.60%. Infrared spectrum characterized that amide groups were generated in the acylated modified phospholipids. Compared with raw phospholipids, the emulsifying stability of hydroxylated and acylated phospholipids were improved in a certain degree.