The invention relates to the technical field of food processing, in particular to a preparation method of a nutrient meal replacement biscuit. The biscuit is mainly prepared from the following raw materials: 10%-65% of wheat flour, 1%-12% of soy protein isolate, 1%-10% of shortening, 1%-8% of white granulated sugar, 1%-8% of polydextrose, 1%-10% of degreased starch, 1%-10% of eggs, 1%-4% of vegetable oil, 1%-8% of collagen peptide, 1%-10% of starch and the balance of whey protein powder, soy protein powder, whey protein, resistant dextrin, quinoa, psyllium seed husk powder, L-arabinose, stachyose, edible salt, ammonium bicarbonate, sodium bicarbonate, phospholipids, food flavor, sucralose, beta-carotene and tert-butylhydroquinone. The biscuit contains rich and balanced nutrients, and meanwhile, the biscuit tastes fragrant, has enough toughness, has effects of promoting appetite and strengthening the spleen, and is easy to digest, low in fat content, good in taste and simple in process.