The invention discloses a cefaclor capsule and a preparation method thereof. The cefaclor capsule provided by the invention comprises a content composed of a cefaclor medicinal raw material, pregelatinized starch, crosslinked sodium carboxymethylcellulose, silicon dioxide and magnesium stearate. The preparation method provided by the invention comprises the following steps: a, weighing various components in the content; b, mixing and sieving the cefaclor medicinal raw material and silicon dioxide, and respectively sieving the other components; c, adding the mixture of the cefaclor medicinal raw material and silicon dioxide and other components into a mixer to pre-mix, and adding magnesium stearate to mix integrally; d, putting the mixture obtained in the step c in the capsule; and e, carrying out aluminium-plastic package. The cefaclor capsule provided by the invention is high in bioavailability and good in stability. The preparation method disclosed by the invention is convenient in source of auxiliary materials, few in kinds of auxiliary materials, low in cost, simple in preparation process and convenient and easy to operate.