The invention discloses tartary buckwheat rice eight-treasure gruel and a preparation method thereof. The eight-treasure gruel adopts tartary buckwheat rice as main raw material and mung bean, red bean, lotus seed, Chinese date, semen coicis, sticky rice, peanut, rock sugar and Chinese wolfberry which are used as both foods and traditional Chinese medicines and have good healthy care function, are added. The eight-treasure gruel comprises the following components in parts by weight: 80-120 parts of tartary buckwheat rice, 50-70 parts of sticky rice, 50-70 parts of semen coicis, 10-30 parts of peanut, 30-50 parts of mung bean, 30-50 parts of red bean, 20-30 parts of lotus seed, 8-20 parts of Chinese date, 100-200 parts of rock sugar, 8-15 parts of Chinese wolfberry and 8-12 parts of dextrin. The invention has the functions of replenishing qi to invigorate the spleen, nourishing the skin, prolonging the life and the like and is especially suitable for the elderly, the weak, people who always get sick middle-aged women and sub-healthy people and is used for nourishing and body-building. The invention is characterized by simple manufacturing process, rich nutrition, convenient edible method, good mouth feeling and low processing cost.