In order to solve the issue of rapid decrease in color, texture and nutritional components of fresh lettuce in the process of selling and storage, the packaging of lettuce was treated with different concentrations of moisturizing fungicide composed of gelatin and peppermint essential oil. According to the daily weight, chromatic aberration, soluble sugar content, titratable acidity, total numbers of colony and vitamin C content of lettuce, the effects of different concentrations of humectant bactericides on the humectant and germicidal efficacy of lettuce were studied. The results showed that 9% moisture fungicide had the best fresh-keeping effect on fresh lettuce, with less loss of quality, soluble sugar, VC and color, and slower growth of colony.