Abstract: Effects of inoculation of arbuscular mycorrhizal fungi on sweet potato yield and quality were investigated in field condition. The results show that the inoculation can increase mycorrhizal fungi colonization, growth and P uptake of sweet potato six weeks after transplantation and also improve the yield and tuber quality of sweet potato on harvest. In summary, the mycorrhizal fungi stain from the native soil performs better than that from exotic soil and mixed strains perform better than the single one.