Abstract:After investigating the ectomycorrhiza of 35 species poplars in Shoaanxi Province,9 species of ectomycorrhizal fung were identified. Experimental results proved that a species of ectomycorrhizal fungus can infect differentspecies of poplars,and that a species of poplar can be infected by different species of fungi.It was also dicovered that in the same small root mantle was formed on the top,and vesicular-arbuscular was formed on the middle and lower parts.This is a special form of mix-mycorrhiza.