Abstract: Enzymatic esterification of glycerol and n-caprylic acid was studied under the catalysis of Novozyme 435 by means of microwave irradiation and conventional heating.Microwave irradiation increased initial reaction rate more than conventional heating did,and the initial reaction rate increased with increasing reaction temperature for both heating modes at 50~75℃.The contents of 2-monoglyceride and 1,2-diglyceride in the microwaved reaction mixture were higher than those in thermo heated reaction mixture,but the irradiation didn't change the lipase's 1,3-specificity.In general the microwave irradiation weakens the 1,3-specificity of enzymatic glycerol esterification of Novozyme 435 and the weakening effect is related to the reaction conditions.By conventional heating,the molar ratios of 1-monoglyceride to 2-monoglyceride (1-MG/2-MG) in the product were 26.9~43.4,and the ratio of 1,3-diglyceride to 1,2-diglyceride (1,3-DG/1,2-DG) were 10.5~19.6;whereas by microwave irradiation,the 1-MG/2-MG were decreased to 16.2~40.4 and the 1,3-DG/1,2-DG became 7.6~15.3.