Abstract: Production of oligomerized polyglycerol fatty acid ester by esterification of industry grade oleic acid with oligomerized polyglycerol catalyzed by phospholipase A1 (Lecitase Ultra) was investigated in this study.The reaction parameters including reaction time, reaction temperature, enzyme dosage, molar ratio of substrates (industry grade oleic acid to oligomerized polyglycerol) and water dosage were studied using response surface methodology (RSM) .Optimum conditions obtained by RSM were as follows:reaction temperature 45℃, enzyme dosage 1.6wt% (of the substrates mass) molar ratio of oliomerized plyglycerol to fatty acid 1:1, reaction time 12h and water dosage 4wt%.Under these conditions, esterification efficiency of the reaction mixture was 56.6%.Some oligomerized polyglycerol fatty acid ester molecular species were identified by HPLC-ESI-MS.