D-isoascorbyl oleate ( IAO) was synthesized by using non-aqueous lipizyme 435 as the biocatalyst and oleic acid as the acyl donor,and the yield of the product was quantified by means of HPLC.Then,the factors influencing the synthesis of IAO were screened by single factor tests,and a Box-Behnken model between the IAO yield and the screened factors ( namely,reaction time,temperature,and molecular sieve dosage) was constructed by means of JMP software.Consequently,this model was used to optimize the synthesis conditions of IAO through the response surface methodology.Finally,the structure of the synthesized IAO was characterized by means of FTIR and NMR.The results showed that,under the optimal conditions,that was,when a oleic acid-to-D-isoascorbyl acid molar ratio of 3∶ 1,a lipase dosage of 3%,an oleic acid concentration of 0. 6mol /L,a reaction temperature of 53. 3℃,a molecular sieve dosage of 150 g /L and a reaction time of 21. 3 h,the predicted IAO yield and the tested one was 78. 40% and ( 74. 65 ± 1. 50) %，respectively,which indicated oleic acid was introduced into the sn-6-hydroxy group of D-isoascorbic acid,and therefore the synthesized IAO was mainly D-isoascorbic acid-6- oleate.