The invention discloses a children mouthwash containing a cetylpyridinium chloride bacteriostatic agent and a preparation method of the children mouthwash. The children mouthwash is prepared from thefollowing components in parts by weight: 4-6 parts of a humectant, 2-1 parts of green tea, 5-7 parts of cetylpyridinium chloride, 5-7 parts of pomegranate seeds, 5-6 parts of edible essence, 3-5 partsof deionized water, 2-4 parts of flos lonicerae, 2-4 parts of menthyl lactate, 4-6 parts of tripolyphosphate, 3-5 parts of mint powder, 3-7 parts of honey, 7-9 parts of mint, and 1-5 parts of malt syrup. The preparation method comprises the following steps: S1, the honey and washed borneol, flos lonicerae and liquorice are put into a container, crushed and stirred to obtain prepared liquid, thenthe liquid is added into 10-12L of water for decoction, decoction with soft fire is conducted for 40 minutes, and then decoction with big fire is conducted for 5-7 minutes; S2, the obtained liquid andmalt syrup are mixed, stirred and cooled for later use; and S3, the flos lonicerae, mint and the green tea are cleaned and cut off, and then mashed, and filtering with gauze is conducted after mashing. The mouthwash adopts natural plant components, is higher in safety and reliability, and has the efficacy of preventing decayed teeth and dental ulcer.