Provided are fibroin mouth wash and a preparation method thereof. The mouth wash is prepared from, by weight, 10-15 parts of fibroin, 12-20 parts of methyl salicylate, 8-12 parts of ethyl alcohol, 1-4 parts of menthol, 2-6 parts of saccharin sodium salt, 4-9 parts of benzoic acid, 1-5 parts of lemongrass essential oil, 1-4 parts of edible essence, 2-8 parts of sorbitol, 4-9 parts of honeysuckle flowers, 4-9 parts of halite, 3-8 parts of sodium benzoate, 2-8 parts of vitamin B, 0.1-0.3 part of allicin and 50-70 parts of deionized water. After honeysuckle flowers are thoroughly washed, deionized water with the weight 2-4 times that of honeysuckle flowers is added, the mixture is heated to 50 DEG C to 60 DEG C, filtering is carried out, and filtrate is obtained; after methyl salicylate, ethyl alcohol, menthol, saccharin sodium salt, benzoic acid, edible essence, sorbitol, halite, sodium benzoate and vitamin B are mixed and stirred, the filtrate obtained in the step 1 and the remaining deionized water are added, the materials are heated to 80 DEG C to 90 DEG C, and a first mixture is obtained; the lemongrass essential oil is dropped into the first mixture, stirring is carried out at the speed of 2,500 rpm to 3,000 rpm, and the mouth wash is obtained. The mouth wash is good in sterilizing effect, and oral hygiene is effectively guaranteed.