The invention discloses meal replacement powder capable of reducing weight and a preparation method of the meal replacement powder. The meal replacement powder capable of reducing weight comprises thefollowing components in parts by weight of 0.1-0.5 part of a white kidney bean extract, 3-5 parts of L-arabinose, 10-15 parts of coix seeds, 10-15 parts of black rice, 10-15 parts of oat, 10-15 partsof millet, 5-10 parts of chenopodium quinoa willd, 5-10 parts of chia seeds, 5-10 parts of linseeds, 12-14 parts of wheat germ powder, 15-20 parts of black beans, 10-15 parts of inulin, 1-5 parts ofsoybean phosphatide, 3-5 parts of a lotus leaf extract, 5-8 parts of bamboo-leaf flavone, and 25-30 parts of isomaltooligosacharide. The preparation method comprises the following steps of firstly, crushing part of the raw materials, then performing wetting, performing puffing, then performing crushing, performing screening, and finally, mixing the rest of the raw materials so as to obtain finished products. The meal replacement powder capable of reducing weight can effectively restrain absorption and conversion of sugar, so that the effect of reducing weight is notable, and besides, the mealreplacement powder is reasonable in nutrient collocation and balanced in function components. The preparation method is simple, convenient, and easy to operate.