Abstract: Quercus liaotungensis is a special species in China as an oak forest tree species, as well as one of the dominant species in the deciduous broad-leaved forest in the warm temperate zone. Gomphidius viscidus and Russula foetens are the ectomycorrhizal fungi which can symbiose and form ectomycorrhizae with Q. liaotungensis in the field. The effects of these two kinds of ectomycorrhizae on the growth of seedlings of Q. liaotungensis were studied in this paper. The seeds of Q. liaotungensis were planted in pots and grown to seedlings in the greenhouse. Five different kinds of inoculation were carried out with G. viscidus and R. foetens to form ectomycorrhizae as follows: CK, non-inoculation; Gv, inoculation with G. viscidus; Rf, inoculation with R. foetens; G-R, inoculation with G. viscidus in one side of the pot and with R. foetens in the other side; G/R, inoculation with a mixture of G. viscidus and R. foetens. After 3 months of inoculation, the height, biomass, root/shoot ratio, net photosynthetic rate, transpiration rate and nitrogen and phosphorus content of the mycorrhizal seedlings and non-mycorrhizal seedlings were measured and compared. All of these results show that ectomycorrhizae can significantly promote the growth of Q. liaotungensis seedlings. The biomass, height, photosynthetic rate and water use efficiency of the mycorrhizal seedlings are higher, but the transpiration rate is lower, than those of non-mycorrhizal seedlings. Nitrogen and phosphorus content in mycorrhizal seedlings are significantly higher than non-mycorrhizal seedlings, being 1.7 and 2.2 times higher, respectively. Ectomycorrhizal formation also changes the allocation ratio of nitrogen and phosphorus to organs of seedlings. Compared with non-mycorrhizal seedlings, nitrogen and phosphorus ratio in the stem of mycorrhizal seedlings decreased, but phosphorus ratio in leaves of mycorrhizal seedlings increased. The acceleration is different among the four kinds of inoculation. Gv is similar to Rf, but Rf is a little higher. The biomass of G-R is significantly higher than Gv and Rf, and the biomass of G/R is higher than G-R. These results demonstrate that co-inoculation with G. viscidus and R. foetens significantly promotes the growth of seedlings, compared to inoculation with G. viscidus or R. foetens alone.