In order to investigate the effect of different concentrations natamycin on the freshness retaining of green juglans,the green juglans were treated with natamycin and stored at(0 ± 0.5) ℃.The result showed that: compared with control group,natamycin could regulate the physiological metabolism of green juglans and had antiseptic effect.It effectively inhibited fruit deterioration.The storage quality of green juglans was evidently improved by natamycin treatments.The study showed that 1 000 mg / L natamycin treatment could reduce effectively the decrease of decay rate.Original color was kept by natamycin treatments.Natamycin 1 000 mg / L treatment can delayed the decrease of MDA content.The activity of catalase(CAT) was promoted effectively,the activities of polyphenol oxidas(PPO) and lipoxygenase(LOX) were maintained at lower level.The natamycin treatments had better preservation effect.