Abstract:The effects of postharvest treatment with oxalic acid（OA） on chilling injury in tomato fruit（Solanum lycopersicum L.） under sub-low temperature were investigated after tomato fruit were dipped in 10 mmol/L OA solution for 10 min at 25 ℃（control fruit were treated with distilled water）and then subsequently stored at sub-low temperature （10 ± 0.5） ℃ for 18 days thereafter transferred to 25 ℃ for 6 days. The results suggested that pre-storage application of OA significantly decreased chilling injury index and disease index， significantly re－ duced MDA content and relative leakage rate in tomato fruit， remarkably inhibited and ethylene production rate， notably enhanced the activities of SOD， CAT and POD， and promoted the contents of proline and soluble protein. These physiological effects suggested that OA improved cold resistance of tomato fruit under sub-low temperature by enhancing antioxidant enzyme activities and increasing the ability of osmotic adjustment， which contribute to maintaining fruit membrane integrity .