The invention discloses diet therapy nutritional porridge powder and a preparation method thereof, and belongs to the technical field of health foods. The diet therapy nutritional porridge powder comprises the following raw materials: corn, wheat, barley, highland barley, brown rice, millet, soybeans, phaseolus calcaratus, mung beans, longevity greens, Ixeris chinensis, apricot, tuber onion seeds, black beans, oat, buckwheat, peanuts, folium mori, sorghum rice, hulless oat, peas, petits pois, mother chrysanthemum flowers, cowpeas, Chinese yam, the seed of Job's tears and pinto beans. The diet therapy nutritional porridge powder can effectively regulate blood sugar, blood pressure and blood fat, has a good effect of treating type II diabetes mellitus, hypertension and hyperlipidemia and does not have any side effect when being eaten for a long time. According to different constitutions of people, the treatment effects are different.