Abstract: Objective:To discuss the effect of salicylic acid on postharvest quality and antioxidant capacity of summer squash. Methods:The summer squash was treated by 50, 75, 100 and 200 μmol/L salicylic acid for 10 minutes respectively, then stored at 4℃, and the summer squash physiological quality index and antioxidant capacity during storage were determined. Results:The summer squash with 50 μmol/L salicylic acid could maintain the vitamin C, chlorophyll and phenolic content compared with the control, and it could reduce the polyphenol oxidase activity, increase the activities of catalase (CAT), peroxidase (POD) and acsorbate peroxidase (APX), enhance the removal ability of free radicals, reduce the malondiadehyde (MDA) content which slower the membrane lipid peroxidation process, and protect the cell membrane. Conclusion:Salicylic acid could maintain a good quality and delay the aging process of summer squash.