Abstract: Studies on the effect and feasibility of application of ectomy-corrhizal fungi on seedlings of Pinus sylvestris var. mongolica Litvin in high-frigid region by inoculating the pure culture of ectomycorrhizal fungi have been conducted. Through three years experiments, it was concluded that ectomycorrhizal fungi could accelerate the growth of the newly planted and replanted seedling. The seedling's height, ground stem, lateral root.number, dry weight and mycorrhization are obviously increased. The longer the period of seedling growth, the more obvious the effect. Analyzing various growing indices, we selcted some good fungi as follows: Russula foetens, Boletus sp., Gomphidius rutilus.