Purple sweet potato (scientific name: Solanum tuberdsm) is also called black sweet potato, and its meat is purple to deep purple. Besides the nutrients of common sweet potato, it is also rich in selenium and anthocyanins. Anthocyanin can prevent and treat 100 diseases, and is known as the seventh essential nutrient after water, protein, fat, carbohydrates, vitamins and minerals. Anthocyanin is the most direct, effective and safest free radical scavenger for preventing and treating diseases and maintaining human health. Its ability to scavenge free radicals is 20 times that of vitamin C and 50 times that of vitamin E. Purple sweet potato will become one of the main raw materials of anthocyanin. Purple potato is very popular in the international and domestic markets, and its development prospect is very broad.