Abstract:The mycorrhizal fungi resources on poplar are very rich．There are 30 species of ectomycorrhizal fungi and 5 species of VA mycorrhizal fungi with which it can form ectomycorrhizae and VA mycorrhizae．It is well known that morphological and anatomical characters of mycorrhizae are closely related with different fungi．Mycorrhizal fungi can enhance the seedling growth，increase water and nutrients absorption，strengthen drought resistance，induce PO(peroxidase)，PPO(polyphenoloxidase)and PAL (phenylalanine ammonialyase)activities of poplar，promote synthesis of resistance materials，and enhance the canker—resistance of poplar．