The invention relates to a slow-release preparation of repaglinide and a preparation method thereof, mainly solving the problem of the slow-release of the insoluble medicament of repaglinide. Hydroxypropyl methyl cellulose, compritol, ethyl cellulose, acrylic resin, caborpl, octadecanol, hexadecanol, stearic acid, sodium carboxymethylcellulose, and sodium alginate, and the like, are used as slow-release materials to prepare the repaglinide into a slow-release formulation; PEG, PVP, HPMC, lactose, mannite, Beta-CD, HP-beta-CD, and the like can also be used as carriers firstly to prepare the repaglinide into a solid dispersion or a clathrate so as to improve the solubility of material medicaments; then the prepared dispersion or clathrate compound and the slow-release materials as well as other auxiliary materials are mixed to prepare the slow-release preparation, thereby delaying the release of medicament, stabilizing the blood concentration, reducing the frequency of administration and enhancing the compliance of patients.