The invention discloses a melbine crystal and a medicinal composition of melbine and saxagliptin and a preparation method thereof. The medicinal composition consists of active ingredients of medicines and a pharmaceutic adjuvant, wherein the active ingredients of the medicines comprise the following components in part by weight: 5 to 30 parts of saxagliptin and 200 to 800 parts of melbine, and the melbine is the melbine crystal; and the pharmaceutic adjuvant comprises a filling agent, a disintegrating agent, an adhesive and a lubricating agent. The melbine crystal used in the medicinal composition has the characteristic of low solubility, so the sustained-release effect of the melbine is realized by using ordinary matrix materials in the medicinal composition prepared from the melbine andthe saxagliptin, the administration safety is improved; and the synergistic effect of the melbine and the saxagliptin is good, so the curative effect is improved. In addition, due to the adoption of few matrix materials, the stability of the medicines is improved.