The invention discloses spirulina white spirit and a preparation method thereof. The spirulina white spirit is prepared from the following raw materials in parts by weight: 400-450 parts of waste distiller's grains, 100-110 parts of rice, 100-110 parts of rice husk, 10-11 parts of red beans, 4-5 parts of buckwheat flour, 10-11 parts of spirulina powder, 4-5 parts of astragalus membranaceus, 2-3 parts of radix acanthopanacis semticosi, 1-2 parts of ginseng, 1-2 parts of rhodiola rosea L., 25-30 parts of yeast for making hard liquor, 0.5-1 part of tea polyphenol, and 0.5-0.7 part of xylo-oligosaccharide. According to the spirulina white spirit and the preparation method thereof, the waste distiller's grains are taken as the raw material for preparing the white spirit, so that the production chain of a yellow rice wine plant is extended, and the prepared white spirit is mellow and plump, and long in aftertaste; the rice husk is subjected to puffing treatment, so that the raw material is loose; the tea polyphenol with selective bacteriostatic action is added, so that bacteria, such as lactic acid bacteria, capable of generating acid is inhabited, while bacterial colony balance of fungi, such as mould, is maintained, and therefore, the problem that the acid content of the fermented materials increases rapidly during stacking and fermenting is solved; the added xylo-oligosaccharide can protect the liver, and in addition, the spirulina white spirit also can boost the immunity.