Arbuscular mycorrhizal fungi (AMF) can form symbiotic relationships with crop roots. Sweet potato (Ipomoea batatas L) is a highly adaptable, high-yielding, and versatile food crop, which is highly dependent on AMF. In order to explore the effects of AMF inoculation on the source-sink relationship, nutrient absorption, and yield of sweet potato during the whole growth period, this experiment took Xu 28 and Claroideoglomus etunicatum, which can establish a good symbiotic relationship, as experimental materials. Two treatments, mycorrhizal and non mycorrhizal, were designed to combine field and pot experiments. Pot experiments were used to analyze the effects of AMF inoculation on the growth of stems and leaves, root tuber expansion, plant biomass, and rhizosphere effects of sweet potato during the entire growth period. Field experiments were used to verify the effects of AMF on root tuber yield and commercialization during the harvest period of sweet potato. The results showed that inoculation with AMF reduced the fresh weight of stems and leaves at seedling stage, flourishing stage, and tuber expansion stage; Significantly increased the root cap ratio at seedling stage, flourishing period, and tuber expansion stage; Significantly increased the rhizosphere effect of slow-release potassium at seedling and tuber expansion stages, and significantly increased the accumulation of nitrogen, phosphorus, and potassium in root tubers at seedling and flourishing stages; Significantly increased the fresh weight of root tubers during the entire growth period. Compared to non mycorrhizal inoculation, the yield per plant during harvest increased by 32.58% in pot experiments and 23.05% in field experiments. Therefore, inoculation with AMF can promote the activation of potassium in the rhizosphere soil, promote nutrient absorption, inhibit the distribution of nutrients and dry matter to the shoot, coordinate the development of source and sink, promote the formation and expansion of root tubers, and improve yield.