The invention provides mometasone furoate gel and a preparation method thereof; the mometasone furoate gel is prepared by the following raw auxiliary materials by weight: 1 parts of mometasone furoate, 150 parts of glycerin, 7.5 parts of carbomer, 1 parts of sodium alginate, 5 parts of laurocapram, 10 parts of triethanolamine, 50 parts of medicinal ethanol, 2 parts of ethylparaben, and the balance of purified water which is added to allow the total weight to be 1000 parts; The advantages of the invention are that: carbomer is used as a water-soluble substrate; triethanolamine is used as a consistency regulator; the product is provided with the advantages of strong adhesion to skin surfaces, good spreading performance, prolongation of retention time of the medicament on skin surfaces; and the effect of the medicament is enhanced. The product is easy to spread and wash, is not greasy, can absorb tissue exudates, and does not interfere normal functions of skin. The product is easy to clean, does not contaminate clothes, and has good stability; the product has smooth appearance, and is transparent and fine; the product has no local irritation; the product has appropriate consistency and viscosity, and is easy to be coated for application; the product has the advantages of convenient carrying, transportation, and storage.