The invention discloses a feed additive for preventing and treating foot-and-mouth disease of beef cattle. The feed additive is prepared from the following raw materials in parts by weight: 10-15 parts of clematis chinensis, 10-15 parts of caulis piperis kadsurae, 8-10 parts of caulis sinomenii, 8-10 parts of cortex acanthopanacis, 3-5 parts of ferula asafoetida, 3-5 parts of dried lacquer, 4-6 parts of portulaca oleracea, 4-6 parts of psidium guajava, 2-3 parts of humulus scandens, 2-4 parts of lonicera hypoglauca, 1-6 parts of rangooncreeper fruit, 12-16 parts of pumpkin seed, 16-18 parts of pericarpium granati, 16-18 parts of orobanche coerulescens, 5-8 parts of cistanche deserticola, 9-12 parts of periostracum cicada, 3-6 parts of asarum sieboldii, 3-6 parts of chrysanthemum, 2-6 parts of equisetum hyemale, 1-4 parts of polygonum aviculare, 2-5 parts of shellac and 20-30 parts of common andrographis herb. The feed additive has the benefits as follows: the feed additive provided by the invention is completely prepared from traditional Chinese medicinal materials, is less in toxic effect, and low in residue, has an obvious effect on preventing and treating diseases of animal husbandry and has a good market prospect.