Chitosan is a natural polysaccharide with multiple biological activities， which can participate in various physiological processes in organisms. The present study investigated the effects of 2% chitosan coating on the storage and nutritional quality， membrane permeability， energy metabolism in fertile orange fruit during storage at 25 ℃. The results revealed that chitosan effectively delayed the decrease of soluble solids and total titratable acid and the increase of weight loss and ratio of soluble solids to acidity， and inhibited the decrease of carotenoids， ascorbic acid， total phenol and flavonoid contents in fertile orange fruit. Further investigation presented that chitosan significantly inhibit the increase of membrane permeability， which is reflected in the lower relative electrical conductivity and malondialdehyde content in fruit tissues. In addition， chitosan maintained a higher energy status， as demonstrated by enhancing adenosine triphosphate content and energy charge， which could be attributed to improve the activities of H+-ATPase， Ca2+-ATPase， succinate dehydrogenase， cytochrome C oxidase during storage. In summary， chitosan can effectively maintain the storage and nutritional quality and delay senescence of postharvest fertile orange fruit by regulating membrane permeability and energy metabolism.