The invention relates to a method for processing instant coarse cereal balanced nutritional flour, which comprises the following steps of: (1) mixing 25 to 30 percent of buckwheat flour, 10 to 15 percent of fagopyrum tataricum flour, 8 to 12 percent of hulless oat flour, 15 to 20 percent of hyacinth bean flour and 30 to 35 percent of pea flour to obtain mixed flour; (2) adding water into the mixed flour and blending to form flour paste, adding solution of CaCl2 to ensure that the pH value of the flour paste is between 6.0 and 6.5, adding 140 to 160u of intermediate-temperature alpha-amylase into each gram of mixed flour, and liquefying at the temperature of between 60 and 65 DEG C to obtain liquefied flour milk; and (3) decoloring the liquefied flour milk, seasoning, and spray-drying to obtain a finished product. The method is simple, easy to operate and master, low in production cost and environment-friendly, the obtained product has high instant and blending performance, is convenient to eat, has an adjuvant therapy effect on senile diseases such as hypertension, hyperlipaemia, cardiovascular and cerebrovascular diseases, diabetes, obesity and the like, and has better effects of dietetic therapy and health care than rice and wheat flour.