Abstract:In order to facilitate the intake of Lettuce in daily life， meet the demand of nutrition and quality of fresh-cut products， the experiment adopted the ultra-high pressure（High Hydrostatic Pressure， HHP，500 MPa， 5 min）combined with carbon dioxide， nitrogen and vacuum processing system respectively to deal with fresh let－ tuce. The chlorophyll content， off color， quality and structure and the change of the microbial of lettuce had been investigated during storage. Cutting fresh lettuce into shreds and blanching 30 s， then weighing， packaging， and heat sealing， after handling under ultra high pressure and controlled atmosphere， storage it in the refrigerator of 4 ℃. Results showed that：the shelf life of fresh cut lettuce processing under ultra high pressure combined with carbon dioxide was 35 days， and chlorophyll content， CIE color - L*a*b* value， quality and structure， were supe－ rior to ultra-high pressure combined with nitrogen and ultrahigh pressure combined with vacuum group，the total number of colonies was lower than the other two groups. Ultrahigh pressure combined with carbon dioxide could improve the quality of the storage of prefabricated lettuce and extend the shelf life of prefabricated lettuce.