Abstract: Effect of AM fungi on the growth of Populus ussuriensis under varied fertilization was studied.The result showed that all of 5 fungi infected the seedling of Populus ussuriensis,and significant difference between the seedling infected by three fungi Glomus intraradices,G.mosseae and G.versiforme and control of Populus ussuriensis seedling in the height,ground diameter and dried biomass under no fertilization. And the height, ground diameter and dried biomass were related with infected rate of fungi.The AM fungi could enhance the absorbing ability of seedling to hard-dissolved phosphorus.The authors found that the growth of seedling was rapid,which was 2.58 times higher than that of the control,under G.sinuosa with Ca（H2PO4）2·H2O (fertilized concentration equalized effective component （P2O5） 0.06 g·kg-1).The combine of G.mosseae or G.intraradices and dissolved phosphorus K2HPO4 (fertilized concentration equalized effective component （P2O5） 0.03 g·kg-1) was the best, while the higher concentration of phosphorus leaded a decrease of biomass. The AM fungi could also enhance absorbing ability of seedling to dissolved nitrogen.The growth of seedling increased under infected by G.versiforme,G.intraradices with KNO3 (fertilized concentration equalized effective component （NO3-） 0.08 g·kg-1) and by G.mosseae,G.intraradices with （NH4）2SO4 (fertilized concentration equalized effective component （NH4+） 0.08 g·kg-1),the biomass was 2.91,2.56,2.7 and 2.4 times of control,respectively.The fertilization of root area was crucial for infected rate of fungi.