The invention discloses a weight-losing tablet and a preparation method thereof, and belongs to the field of weight-losing medicines. The weight-losing tablet is prepared from the following components in parts by mass: 20 to 25 parts of white kidney bean, 30 to 35 parts of tangerine, 20 to 25 parts of raspberry fruit, 5 to 8 parts of opuntia ficus, 5 to 8 parts of folium nelumbinis, 1 to 2 parts of xylitol, 1 to 2 parts of sorbitol, 1 to 2 parts of sucralose, 2 to 5 parts of microcrystalline cellulose, 1 to 2 parts of magnesium stearate, and 0.3 to 0.5 part of edible essence. The preparation method is characterized in that in the granulating process, a granulating device by using edible vinegar as a huddling liquid is adopted. The weight-losing tablet has the advantages that the functions of controlling body weight, decreasing body lipid and reducing weight are realized; the intestine functions are regulated; the functions of resisting oxidizing and delaying aging are realized; the glycemic index of foods is reduced, and the blood glucose value is balanced; the heat absorbing is controlled; the blood lipid is regulated, the fat settling of artery is inhibited, the multiple functions of improving the health of cardiovascular vessels and the like are realized, the health and safety effects are realized, the nutrients required by a human body are maintained, and the red-face, luster-skin, health and nature effects are realized.