The invention relates to a herbal injection for treating pig's blue-ear disease. The herbal injection is prepared from the following drug substances by weight: 1 to 2 parts of sweet wormwood, 2 to 4 parts of scutellaria, 4 to 6 parts of heartleaf houttuynia herb, 4 to 6 parts of spreading hedyotis herb, 4 to 6 parts of echinacea, 4 to 6 parts of astragalus, 2 to 4 parts of atractylodes macrocephala, and 1 to 2 parts of liquorice. The drug substances are smashed; blending and three-time water cooking extraction are carried out; the three filtrates are combined; the mixture is concentrated for alcohol precipitation; the pH value is adjusted; decolorization is carried out with activated carbon; tween-80 is adopted to facilitate dissolution; a fixed quantity of a preservative is added; uniform stirring, filtering, filling and sterilizing are carried out to obtain the herbal injection which has an excellent effect on treating pig's blue-ear disease.