This study aims to research the protective effect of chitosan on the fruit. With the preservation experiment on the Kiwifruit, apple, mango and honey peach, it can show that the fruit weight loss rate and decay index of chitosan protective agent are decreased at different degrees. Meanwhile, the fruit hardness decreased rate is dropped. The research illustrates that the nature of chitosan film property, antibacterial activity and respiration inhibition can be applied in the fruit reservation field.