To develop a new type of fruit and vegetable preservative with low toxicity and harmLess, the bio-liquid was used as the main experimental material, and the antibacterial effects and mechanism of bio-liquid on the Colletorichum orbiculare and the effect on the preservation of muskmelon were studied. The results showed that the bio-liquid had obvious antibacterial effect on the Colletorichum orbiculare, and the EC₅₀ and EC₇₀ ere 1.8% and 2.4%, respectively. The bio-liquid could destroy the membrane structure of the Colletorichum orbiculare and the rupture the cell membrane, which caused the exudation of proteins, nucleic acids, and carbohydrates. Treated with bio-liquid could delay the decrease of pulp’s hardness, soluble solid content, titratable acid content, besides, it could inhibit polyphenol oxidase activity and polygalacturonase activity, and also delay the consumption of phenolic substances and inhibit the increase of soluble pectin content. The higher the concentration of bio-liquid was, the more obvious the effect of muskmelon preservation had.