The invention belongs to the technical field of wine making, and provides black grain wine and a brewing method thereof. The black grain wine provided by the invention consists of the following components in parts by weight: 30-50 parts of sorghum, 5-10 parts of black glutinous rice, 5-10 parts of black rice, 3-8 parts of black corn, 1-5 parts of triticale, 0.5-3 parts of black jujubes, 0.5-3 parts of black sesame, 0.5-2 parts of watermelon peel, 3-8 parts of red beans, 1-5 parts of waxberries, and 0.1-1 part of tamarind fruits. The preparation method comprises the following steps: crushing the sorghum, the black glutinous rice, the black rice, the black corn, the triticale, the black sesame and the red beans, performing mixing, adding water, and performing boiling and concentrating to obtain a wet mixture; grinding the watermelon peel, the waxberries and the tamarind fruits, adding water, and performing boiling and concentrating to obtain a fruit paste; and adding water into the wet mixture, performing secondary boiling, spreading and airing the boiled material to room temperature, adding yeast powder to obtain a to-be-fermented material, and performing fermentation treatment anddistillation treatment to obtain base liquor, soaking the fruit paste in the base liquor for 30 days, and performing filtering and filling to obtain the black grain wine. The technical scheme solves the problems of poor color and luster and poor taste of black wine in the prior art.