Abstract: Poplar is an important forest specie. By inoculating ectomycorrhizal fungi into the roots of poplar seedlings, the effects of nine ectomycorrhizal fungi on the growth of four poplars and mycorrhiza infection rates by different inoculation methods was studied. The results indicated that ECM fungi Xrocomus chrysentero (Xc), Boletus edulis (Be), Pisolithus tinctorius (Pt) and Laccaria aemthystea (La) could form mycorrhiza significantly on four poplars. Xc had the best capacity of mycorrhizal colonization among the four poplars. Rl could form mycorrhiza significantly on poplar I-69. The ability of Pt and La to form mycorrhiza was worse than that of Xc and Be. Scleroderma luteus (Sl), Leccinum scabrum (Ls), Boletus speciosus (Bs), Calvatia craniiformis (Cc) and Rhizopogen luteous (Rl) could not easily colonize poplar roots on sterilized soil, but they could form mycorrhiza on non-sterilized soil. Mycorrhizal infection with drilling method was higher than that with transplantation method and dipping root method. Populus simonii Carr could form mycorrhiza with majority of nine mycorrhizal fungi. Poplar I-72 and Poplar NL-351 had the highest compatibility with Pt. Poplar I-69 showed the highest compatibility with Xc. The study suggested that the optimal ECM fungi for poplar I-69, poplar I-72 and poplar NL-351were Be, Xc and Pt respectively. For Populus simonii Carr., they were Xc and Be. With inoculating the ectomycorrhizal fungi, growth of the poplar could be stimulated significantly.