Abstract: Three ectomycorrhizal fungi, Boletus griseus, B. sp. and Suillus grevillei, were chosen to be studied on ecological adaptability to environmental factors, such as temperature, pH, salt concentration and water potential. Besides, the 3 fungi were used in pure culture synthesis of Pinus tabulaeformis and P. elliottii ectomycorrhizae.Generally, pH and salt concentration had slight effects on the growth of ectomycorrhizal fungi but temperature and water potential had strong effects in the ecological adaptability experiments using 3 fungi. B. sp. and S. grevillei displayed their strong adaptability in varied ecological conditions. In addition, it's evident that PEG-4000 can accelerate the growth of ectomycorrhizal fungi in liquid.In the pure culture synthesis, five ectomycorrhizae were formed, in which P. tabulaeformis-B. griseus were discovered for the first time. P. tabulaefor-mis-S. grevillei and P. elliottii-B. griseus are better ones of the 5 mycor-rhizae.