The effects of three concentrations(1.0%,1.5%,2.0%) chitosan coating treatments on storage quality and post-harvest physiology of Newhall navel orange stored at low temperature(7±1)℃were investigated.The results showed that chitosan treatments could delay the loss of soluble solids content(SSC),vitamin C content and titratable acid in fruits.The respiration rate of fruits was well controlled.The loss of water and decay rate of fruits were also inhibited.The loss of antioxidant enzymes SOD and CAT activity was delayed and thus prevent the degradation of Newhall navel orange.The best treatment was 2.0% Chitosan.