This paper investigated the effect of different concentrations(800mg/L、1200mg/L) of natamycin on the quality of Broccolis stored at-1℃~1℃.The physicochemical indexes and nutrition components of Broccolis were detected every 10days.The results showed that the soluble solids,vitamine C and chlorophyll content of broccolis by natamycin treatment decreased less than that just by cold storage.Natamycin could inhibit the increase of respiratory intensity,increased superoxide dismutase(SOD) activities and slowed down polyphenol oxidase(PPO)activity and decreased cell membrane permeability.These results showed that cold storage combined with natamycin treatment could delay ripening of Broccoli,wherein the storage effect of Broccolis with 1200 mg/L natamycin treatment was better than that with 800mg/L.