The invention discloses catechinic acid mouth wash and a preparation method thereof. The catechinic acid mouth wash is prepared from catechinic acid, calendula officinalis, roselle, chrysanthemum buds, mint, ethyl alcohol, amino acid, a surfactant, sodium fluoride, a preservative and water. The preparation method comprises the following steps: brewing the calendula officinalis, the roselle, the chrysanthemum buds and the mint with water according to the ratios under the water temperature of 80-90 DEG C for 3 to 5 min, extracting soup, cooling the soup, so as to obtain tea soup; mixing the tea soup, adding the catechinic acid, the ethyl alcohol, the amino acid, the surfactant, the sodium fluoride and the preservative according to the ratios, adding water to 100 percent, and uniformly mixing the materials. According to the catechinic acid mouth wash and the preparation method thereof, the catechinic acid, the calendula officinalis, the roselle, the chrysanthemum buds, the mint, the ethyl alcohol and the amino acid are organically combined, and the optimal use amounts of all components are determined, so that an effect of refreshing the oral cavity is achieved, and ozostomia can be eliminated fundamentally to protect the oral cavity; meanwhile, the catechinic acid mouth wash has natural components, does not contain essence and does not have side effects on a human body.