Ponkan fruit were used as test materials, which were treated with different doses (0.25, 0.50, 0.75, 1.00 kGy) of γ-irradiation to study the irradiation intensity on the postharvest physiology and biochemistry of the fruit. The results showed that suitable irradiation treatment effectively reduced weight loss ratio of Ponkan fruit, inhibited the respiration intensity and the increase of the malondialdehyde (MDA) content, delayed the decline of soluble solid, titratable acid and Vc content, maintained the activities of peroxidase (POD) in fruits. The best result was obtained when irradiation dose was 0.5 kGy.