In order to explore the fresh-keeping effect of EGCG on postharvest longan, the fruits of postharvest longan were soaked in 1 mmol/L EGCG solution for 5 minutes and stored at 25 ℃. On the 2, 4, 6 and 8 days of the storage period, samples were taken to determine the autolysis index of the pulp, the content of endogenous antioxidants, and the activity of antioxidant enzymes. The results showed that at 6 and 8 days after exogenous EGCG treatment, the autolysis index of longan fruits after harvest decreased by 22.56% and 11.70% respectively, compared with the control group; at 8 day after exogenous EGCG treatment, TSS and TA in the pulp were respectively 1.16 and 1.17 times than that in the control. Furthermore, EGCG treatment significantly increased the activities of DHAR and GR, and up-regulated the relative expression of enzyme genes such as DlDHAR and DlGR.