The invention discloses an application of a composition packet in preparing food, medicines, health care products and nutrition for improving and treating human Prader-Willi syndrome. The composition packet includes the following compositions each of which is in a uniform dose unit form convenient for dose administration, and each dose unit form is a single-dose physical dispersing unit, wherein the first composition consists of coix seeds, oats, buckwheat, semen lablab album, yellow corn, semen phaseoli, soybeans, rhizoma dioscoreae, fructus ziziphi jujubae, peanuts, lotus seeds and fruits of Chinese wolfberry; the first composition can also consist of rye, wheat, quinoa and hulless barley; the second composition consists of fructus momordicae charantiae, soluble dietary fibers and oligosaccharide; and the third composition consists of soluble dietary fibers and oligosaccharide. By reasonably adjusting the diet nutrition of patients with the human Prader-Willi syndrome, the purposes of relieving, removing, remedying, preventing or improving the symptoms of the human Prader-Willi syndrome and recovering health can be achieved.