In our study, the fungus T. virens appeared to have an advantage in the competition with S. luteus. For this reason, root colonization was inhibited when the two fungi were simultaneously applied. So the colonization rate of S. luteus ? T. virens was lower than the colonization rate of S. luteus 30 days ? T. virens treatment. However, the difference between the two treatments was not very significant, indicating that the two strains can be compatible. Previous studies have demonstrated that the plant growth can be improved by mycorrhizal fungi and other beneficial fungi [6, 24, 25, 39, 40]. Inoculation with S. luteus or T. virens alone improved the growth of the P. sylvestris var. mongolica seedlings, affecting factors such as plant height, collar diameter, dry weight, and wet weight compared to the control. Vigorous growth was observed after inoculation with S. luteus and T. virens compared with the nonmycorrhizal control obviously, particularly for the S. luteus 30 days ? T. virens treatment. This result showed that treatment with S. luteus 30 days ? T. virens displayed the highest potential. When the mycorrhiza of S. luteus and seedlings was established (30 days after inoculation), the T. virens was introduced; it created increased synergies.