The invention relates to an amino acid nanometer facial cleanser rich in soybean polysaccharides and a preparation method thereof. The amino acid facial cleanser comprises the following compositions:water, leucine, glycine, valine, serine, threonine, histidine, alanine, arginine, sericin, sodium methyl cocoyl taurate, cocoamidopropyl betaine, soybean polysaccharides, honey extract, tocopherol, ginger, phenoxyethanol and essence. The facial cleanser has the advantages that: a plurality of amino acids are used as raw materials, soybean polysaccharides are added after the amino acids are compounded, and the prepared amino acid nanometer facial cleanser rich in soybean polysaccharides not only can realize high-efficiency cleaning effect, but also can reduce the application amount of a surfactant and reduce skin irritation, has high safety, and can be used by children and for sensitive skins. The compounded amino acids are matched with the soybean polysaccharides so as to have better moisturizing and anti-sensitization effects. The facial cleanser has mild performance, good stability, and no irritation to skin.