Based on the color of sweet potato flesh, there are red sweet potatoes, white sweet potatoes and purple sweet potatoes. Sweet potato belongs to the order Tubular Flowers, an annual herbaceous plant of the Convolvulaceae family. It is more than 2 meters long and lies flat on the ground. The leaves are usually wide oval, 4-13 cm long and 3-13 cm wide. The corolla is pink, white and light. Purple or violet, bell-shaped or funnel-shaped, 3-4 cm long, the capsule is oval or oblate, with false septa, divided into 4 chambers, with underground tuberous roots, spindle-shaped roots, and khaki or purple-red outer skin. Sweet potatoes are rich in protein, starch, pectin, cellulose, amino acids, vitamins and various minerals, and are known as "longevity food". The sugar content reaches 15%-20%. It has anti-cancer, heart protection, prevention of emphysema, diabetes, weight loss and other effects. Li Shizhen's "Compendium of Materia Medica" of the Ming Dynasty recorded that "sweet potatoes can replenish deficiency, strengthen the spleen and appetite, and strengthen kidney yin", and also said that people living in the sea can live longer by eating it. Traditional Chinese medicine regards sweet potatoes as good medicine.