The invention discloses a formula and preparation method of protein fruit-vegetable-taste milk shake having the efficacy of reducing weight. According to the formula, konjaku flour, walnut kernels, blueberry fruits, raspberries, strawberries, papayas, bananas, pineapples, kiwi fruits, coconuts, passion fruits, black currants, mangoes, pumpkins, beetroot, matcha, avocado pears, taurine, skimmed milk powder, soy protein isolate, whey protein, various medicinal and edible foods, various vitamins and minerals, fructo-oligosaccharide and inulin are used as raw materials, and through working procedures of refining, grinding, homogenizing, freeze drying, crushing, mixing, packaging and the like, the protein fruit-vegetable-taste milk shake is prepared. The protein fruit-vegetable-taste milk shakemeets eating requirements of consumers in the respects of satiety and mouth feel, and the appetite is reduced; besides, the product namely the protein fruit-vegetable-taste milk shake is rich in components of dietary fibers, unsaturated fatty acid, protein and the like, so that the effects of reducing weight and increasing muscle can be effectively exerted; and the product is rich in various nutrient components, so that the protein fruit-vegetable-taste milk shake can meet daily nutrient requirements of organisms as meal replacement. The product also has the functions and effects of reducingfat deposition, reducing weight, restraining obesity generation, enhancing organism immunity and the like.