The invention relates to a composite brewing cereal powder and a preparation method thereof. The composite brewing cereal powder is mainly prepared by the following raw materials: glutinous rice, seedof Job's tears, quinoa, black rice, corn, buckwheat, oats, sorghum rice, yellow rice, brown rice, barley, wheat, wheat germ powder, soybeans, mung beans, dried jujube, white sesame, peanut, Poria cocos, hawthorn, cassia seed, root of kudzu vine, wolfberry, yam (dried), carrot, chestnut, blueberry, Hericium erinaceus, black fungus, white fungus, mushroom, Arimillaria mellea, pleurotus eryngii, peach kernel, raisin, honey, tangerine pericarp (dried orange peel), radish seed, lotus seeds, chrysanthemum, oyster shell, lily, hemp seed, rose, flos lonicerae, oligofructose, and barley seedlings. Thecomposite brewing cereal powder is prepared by screening, drying, pulverizing, frying, baking, compounding, packaging and the like, and contains the comprehensive nutrient components necessary for the human body, is easy to be digested and absorbed, can supplement the daily energy required by the human body, and can improve sub-health status.