Abstract: The optimum hydrolysis conditions of lipase Bakezyme LPF on soyabean powder phophatide in aqueous phase were investigated by the single factor experiment and orthogonal experiment using acid value as index as follows:reaction temperature 50℃, reaction time 8h, enzyme concentration 8%, p H value 5.0, and concentration of soybean phosphatide solution 25mg/m L. Under above conditions, the acid value of soybean phosphatide hydrolysis product was 65.2mg KOH/g. The fatty acid composition and content of soybean phosphatide before and after hydrolysis were analysed by gas chromatography-mass spectrometry and the result showed that the content of saturated fatty acids decreased significantly while unsaturated fatty acids increased significantly, and illustrated that lipase Bakezyme LPF mainly hydrolized fatty acids of soybean phosphatide in sn- 1 and had the property of phospholipase A1. Phosphatidylcholine ( PC) and phosphatidylethanolamine (PE) contents of soybean phosphatide before and after hydrolysis were analysed by high performance liquid chromatography and result showed that PE and PC were hydrolized into lysophospholipids.