Abstract: The quality of fresh-cut fruits and vegetables decreased rapidly due to cutting-wound damage.Occurrences of decay mainly were caused by microorganism 's growth and reproduction. Natamycin as a natural antifungal biological preservative could inhibit pathogenic molds of fresh-cut fruits and vegetables had been investigated. In this work, fresh-cut lettuces were dipped in and spray with natamycin solution at 200mg/L.These results indicated that fresh-cut lettuces treated with natamycin could be promising in reducing the mols populations, also slowed down the phenolic, flavonoids, anthocyanin degradation and the activity of polyphenol oxidase (PPO) , phenylalnine ammonialyase (PAL) , inhibiting accumulative of malondialdehyde (MDA) . These results showed that natamycin treatment would delay ripening and inhibit decay of fresh-cut lettuces, fresh-cut lettuces with spray treatment was better than dipped in natamycin solution at 200mg/L.