Lychees (cv. Huaizhi, Nuomici, Guiwei) were stored for over 30 days at temperature 4℃, then the superoxide dismutase (SOD) activity, membrane permeability, superoxide radical and Malon-dialdehyde (MDA) content in the pericarp were determined, and the browning index of the pericarp was also investigated. The results showed that the browning index and membrane permeability were greatly increased with the extension of storage; SOD appeared to decline at first, then raise, and at last descend with the extension of storage. In contrast, Malon-dialdehyde (MDA) content and superoxide radical producing rate changed regularly, that is to say, they raised first, then declined and at last raised again with the extension of storage and browning. MDA and superoxide radical had positive correlation with the browning; however SOD activities had a negative correlation with the browning of Lychee pericarp. Furthermore, SOD activity has a certain adverse trend with MDA content and superoxide radical producing rate. These indicated that SOD, MDA, superoxide radical and plasama membrane permeability could be considered as important indices in determining the browning of Lychee pericarp.