The invention discloses nutritional rye and purple sweet potato balls and a preparation method thereof. The nutritional rye and purple sweet potato balls are characterized by comprising the following raw materials in parts by weight: 200-210 parts of purple sweet potatoes, 100-110 parts of pumpkins, 10-11 parts of brown sugar, 5-6 parts of lard oil, 5-6 parts of thick broad-bean sauce, 20-25 parts of armeniaca dulcis, 7-8 parts of asparagus lettuce, 10-11 parts of longans, 25-26 parts of dried bean curds, 10-11 parts of soybean sauce, 260-300 parts of rye flour, 20-22 parts of tomato paste, 4-5 parts of ganoderma lucidum spore powder, 2-3 parts of gynostemma pentaphylla, 1-1.4 parts of codonopsis pilosula, 1.3-1.5 parts of rhizoma polygonati, 0.9-1 part of cynanchum mooreanum hemsl., 1-1.2 parts of thyrocarpus sampsonii hance, 5-6 parts of distillers' grains, 50-55 parts of yellow mud and 10-12 parts of nutritional additives. Fillings prepared from pumpkins, armeniaca dulcis and the like are added, so that the nutritional rye and purple sweet potato balls are heavy in flavor; meanwhile, tomato paste is also added, so that the balls are sour, sweet and tasty; additionally, the main raw materials of purple sweet potatoes and rye flour are rich in selenium element, and traditional Chinese medicine such as gynostemma pentaphylla is matched, so that the balls can achieve the effect of preventing the cancer.