The invention discloses mouth wash for preventing and curing periodontitis and a preparation method thereof, and belongs to the technical field of mouth care products. The mouth wash is prepared fromthe following raw materials in percentages by weight: 4% to 6% of stringy stonecrop, 3% to 5% of sticktight, 2% to 7% of bitter gourd roots, 4% to 8% of fructus trichosanthis seeds, 8% to 10% of lemonseeds, 5% to 10% of fulvic acid, 0.1% to 0.3% of potassium sorbate and the balance of deionized water. The mouth wash disclosed by the invention contains various natural extracts, is mild and comfortable in mouth feel and little in side effect on mouth and teeth, and has a good effect of preventing and curing periodontitis; the raw materials of the mouth wash are wide in resources and scientificin proportioning, and the manufacturing method is simple and reasonable.