Abstract: The postharvest fruit browning of Pyrus bretschneideri Rehd was a Physiological disease in storage. It concerned not only the content and compartmentation of phenolics compounds and polyphenol oxidase but also the change of cell membrane structure. The browing mechanism and controlling methods of Pyrus bretschneideri Rehd were also researched in this discussion. The result indicated that the browning index of Pyrus bretschneideri Rehd was positively related to Polyphenol oxidase, negatively related to Phenolics compounds, positively related to the relative conductance rate in CA storage.