Abstract: The enzyme browning induced by polyphenol oxidase( PPO) affects nutrition,flavor and economic value of lotus seed.Insight into the mechanism of the enzyme browning is based on the structure and characteristic of PPO.Therefore,to obtain a fairly pure PPO is the purpose of this study.The comparation between four methods of extracting lotus seed PPO was made,homogenization post- acetone extraction method was better in PPO specific activity and maintaining the total activity.The results of optimizing homogenization post- acetone extraction were as follows: the ratio of solid- to- solvent 1 ∶ 5,extract time 2 h,phosphate buffer containing 0.8% Triton X- 100 and 2%PVPP at p H7,and the specific activity was 294.40 U / mg.The rude extraction was purified by DEAE Sepharose Fast Flow ion exchange column chromatography and Sephadex G-75 gel filtration chromatography.The specific activity of purified PPO was 7926.68 U / mg,a purification factor of 26.92,yield was 38.48%.The molecular weight of this enzyme was about 58 ku.