The invention discloses a method for preparing 2-deoxy-D-glucose. According to the method, D-glucosamine which is low in price and easy to obtain serves as a starting material, p-anisaldehyde is used for protecting amino, pyridine serves as a solvent under catalysis of 4-dimethylaminopyridine (DMAP), acetic anhydride serves as a reactant for acetylation protection of all hydroxyl groups on D-glucosamine, protecting groups on the amino are removed under the acidic condition to obtain 1,3,4,6-tetra-o-acetyl-2-glucosamine hydrochloride, and the amino is further converted into isothiocyano with PhOC(=S)Cl; AIBN serves as an initiator, a free radical reaction is conducted by means of tris(trimethylsilyl)silane (TTMS-H) and 1,3,4,6-tetra-o-acetyl-2-glucosamine hydrochloride, and finally acetyl is removed to obtain 2-deoxy-D-glucose. According to the novel synthetic route, raw materials are easy to obtain, operation is easy, no chromatographic column separation is involved, the total yield is high, cost is low, and the method is suitable for large-scale production. The preparation method is simple in product aftertreatment, the product is easy to separate, and large-scale production is easy to achieve.