Using sweet corncob polysaccharide and chitosan as coating materials, glycerol and gum arabic as thickeners, a polysaccharide-based composite coating film was prepared. The tensile strength of the coating film was used as an indicator to determine the ratio of chitosan to acetic acid 1:100, the mass concentration of gum arabic 0.15 g/mL, the ratio of chitosan solution to gum arabic solution 1:2, the amount of glycerol added 1.8 mL, and the amount of sweet corncob polysaccharide nano emulsion added 1.2 mL.The sweet corncob polysaccharide-based coating film prepared by the response surface optimization formula has a tensile strength of 92.37±2.07 KPa.The coating film was applied to the preservation of Millennium fruit, kumquat and grape, and the preservation effect was studied. The spoilage rate, weight loss rate, color difference, polyphenol content, titratable acid and soluble solids of fruit were used as evaluation indexes. Principal component analysis showed that the cumulative variance contribution rate of PC1 and PC2 was 92.353% . It showed that the coating has a certain effect on fruit preservation, which provides a theoretical basis for the application of sweet corncob polysaccharide nano emulsion in coating preservation, and can provide some feasible support for subsequent research.