In order to improve the apple postharvest resistance to mechanical damage to reduce storage losses,to explore the application of chitosan coating on fruit and vegetable preservation.With Fuji apple as material,by artificial simulation mechanical injury trials,we researched the flesh browning,related enzyme activities and resistance substances of Fuji apple at room temperature storage conditions.The results showed that:the chitosan coating reduces mechanical wound expansion,increases mechanical injury total phenol content of fruit,decreases PPO activity,so as to effectively inhibit the browning of the mechanical injury apple flesh during storage.The chitosan coating increases the mechanical injury apple POD and PAL activities,slows the decline of the phenolic substances,promotes the synthesis of lignin.Chitosan coating can effectively prevent enzymatic browning of mechanical injury apple during storage,reduce the accumulation of harmful substances in the pulp tissue,and promote the formation of callus.Thus the chitosan coating can increase the resistance to mechanical injury apple,effectively delay senescence.