Abstract: In this paper, characteristics of drought tolerance in mycorrhizal fungi inoculated and uninoculated seedlings of Pinus armandii Franch were studied contrastively by means of the artificial simulation method of water stress. The results showed that: with the aggravation of water stress, the permeability of membrane and MDA content increased greatly of two p. armandii Franch seedlings, but compared with the uninoculated seedling, the ascending range of mycorrhizal fungi seedlings was much smaller, while the chlorophyll content, the activaty of NR, the root activity and water content decreased, the descending range was that the former was lower than the latter. It indicated that synthetically drought tolerance of mycorrhizal fungi was stronger than that of uninoculated uninocotion.