The preparation method comprises the following steps: step 1, preparing a certain amount of wormwood juice, mosquito-repellent vanilla juice, platycladus orientalis juice, rosemary juice, artemisia capillaris juice, mint juice and eupatorium fortunei juice for later use; according to the invention, the natural plant extract is an important secondary substance of plants, and has the characteristics of various biological activities, natural inoculation action mechanisms, pure nature, no pollution and the like. Juice extracted from the raw materials of wormwood, mosquito-repellent vanilla, platycladus orientalis, rosemary, artemisia capillaris, mint and eupatorium has various natural antibacterial, anti-inflammatory, itching-relieving and detumescence components, and various volatile oil is natural raw materials, so that the volatilized smell not only can naturally repel mosquitoes, but also cannot enable the mosquitoes to generate resistance, and the mosquito-repellent effect is lasting and effective.