Abstract: A simple and efficient method was developed to separate lysozyme from egg white.And high purity lysozyme was prepared by the developed method.The steps of this method are as follows： diluting egg white with five times volume of phosphate buffer solution （PBS;pH 6.5）;stirring for 30 min;adjusting pH value to 4.6;heating at 100 ° C for 20 min;cooling and centrifugation;treating supernatant by fractional precipitation with ammonium sulfate.The precipitate produced with 40%-80% saturated ammonium sulfate was electrophoresis-pure lysozyme.