The invention relates to a sophora alopecuroide additive and a preparation method thereof. The sophora alopecuroide additive comprises the following components: sophora alopecuroide, honeysuckle, liquorice, chrysanthemum, lophatherum gracile, Chinese yam, medlar, hawthorn, honey, crystal sugar and water. The sophora alopecuroide additive complies with the traditional compatibility principle, has the effects of relieving summer-heat and promoting diuresis, reducing internal heat and removing retention, clearing heat and releasing toxin, resisting bacteria and eliminating inflammation, resisting viruses, resisting tumor, enhancing immunity and the like, and is particular in material selection, strict in preparation technology and absent in adverse side effects.