The invention discloses a brewed oat flour and making method thereof. The product comprises following raw materials by weight: 650-700 parts of naked oat flour, 150-200 parts of soybean flour or black soya bean flour, 50-60 parts of pea flour, 40-50 parts of buckwheat flour, 4-15 parts of walnut kernels, 3-9 parts of pine nut kernels, 1-8 parts of pumpkin seeds, 2-10 parts of red dates, 4-6 parts of pseudostellaria roots, 3-7 parts of astragalus roots, 3-6 parts of Chinese angelica and 3-12 parts of Chinese yam. The brewed oat flour provided by the invention contains a plurality of cereal crops, and has the characteristics of high protein, high dietary fiber and low carbohydrate; when eating, only boiled water is needed for brewing with stirring, the product can be eat, and tedious eating modes, such as steaming, boiling, decocting, baking and frying are changed with simple operation and saved time; the invention also has health preserving and health care effects, and long-term eating can regulate menstruation, moisten face, invigorate spleen, inhibit dampness, boost blood, supplement vacuity, reduce cholesterol, expel toxin, nourish face, resisting aging, and reduce incidence of diseases, such as diabetes, coronary heart disease, arteriosclerosis and hypertension.