The invention discloses alum-free sweet potato vermicelli capable of invigorating stomach and promoting digestion. The alum-free sweet potato vermicelli is characterized by being prepared from the following raw materials in parts by weight: 400-450 parts of sweet potato starch, 20-22 parts of green bean starch, 1.6-2 parts of xanthan gum, 1.2-1.4 parts of composite phosphate, 20-30 parts of carrot, 10-14 parts of tomato, 14-18 parts of hyacinth bean, 15-25 parts of mushroom, 3-5 parts of lilium pollen, 5-7 parts of gelatine powder, 10-14 parts of water caltrop starch, 14-16 parts of polished round-grained rice, 8-10 parts of coloured malt, 6-8 parts of Chinese yam, 5-7 parts of medicated leaven and 7-9 parts of hawthorn. By the method of replacing alum with green bean starch, xanthan gum and composite phosphate for the sweet potato vermicelli, not only can the toughness and elasticity of vermicelli be increased, but also the bar breaking rate of vermicelli in boiling is reduced; the added raw materials including carrot, tomato, hyacinth bean and the like are capable of increasing the nutritional value of vermicelli; the added traditional Chinese medicine components including coloured malt, Chinese yam and the like are capable of enabling the vermicelli to have the health efficacies of invigorating stomach and promoting digestion and the like, and increasing the economic value of the sweet potato vermicelli.