Abstract: Objective: In order to find the effects of nitric oxide on the storage qualities and antioxidant activities of postharvest peach fruits. Methods: The flesh firmness, contents of cell wall pectins, soluble sugars, titratable acids, total phenols and flavonoids, as well as the antioxidant abilities of peach fruits were investigated during cold storage after NO donor (sodium nitroprusside) and its scavenger (c-PTIO) treatments. The correlation between different qualities, antioxidant compound contents and antioxidant activities were also analyzed. Results: Results showed the firmness and content of sodium carbonate soluble pectin of SNP treatment peach fruits were significantly higher than the control group during 20~30 days of storage. SNP treated peach fruits possessed more contents of total phenols and flavonoids than the control and c-PTIO treated peaches stored 30~40 days. The antioxidant activities determined by 3 methods of SNP treated peaches reached the highest values at 30th day and were significantly higher than the control and c-PTIO treatment. Significant positive correlation existed among total phenol contents and 3 antioxidant activities. Conclusion: SNP treatment maintains the storage qualities and antioxidant activities of peach fruits during cold storage. c-PTIO treatment promotes the quality deterioration of peach fruits. The research results provide a theoretical basis for revealing the mechanism of peach fruit quality change during cold storage and helping to develop postharvest preservation technology.