Abstract: The enzymatic browning during storage in Cuiguan pears was studied. The results indicated,During the storage the phenol compounds were synthesized in Cuiguan pears at first ,then they decreased. The activity of polyphenol oxidase(PPO) took on an increase firstly, then fell down. Following the decrease of phenol compounds, the browning reaction took place. The oxidization of phenol compounds promoted by PPO was considered the cause. The cold storage(0℃)could delay the senescence、softening and browing.