To research the physiological responses to drought stress of mycorrhizal seedlings of Rhododendron annae mycorthiza, its seeds were inoculated with four ERM fungi (TY02, TY21, TY29, TY35) respectively, with non– inoculation as the control，and the relative water content, water saturation deficit, the adjustment of osmotic substances(soluble sugar, soluble protein, proline), the enzymatic activity of SOD, MDA content, the physiologic index and biochemical criterion of photosynthetic pigment of Rhododendron annae leaves were measured under drought stress. The results showed that inoculation of ERM fungi could improve leaves relative water content and reduce water saturation deficit. In the 15th day after inoculated with TY29, the relative water content of the leaves was increased by 91.62%; after re–watering, the relative water content of the leaves treated with TY35 was 154.6% higher than that of the control group. Inoculation with ERM fungi could significantly increase the soluble sugar, proline, soluble protein and other osmotic adjustment substances of Rhododendron annae. Inoculation with ERM fungi could enhance the adaptability of Rhododendron annae to drought stress by increasing SOD activity and reducing the MDA content. In the 10th day, SOD activity inoculated with TY35 was the best, it was 69.4% higher than that of control group. In conclusion, the abilities of drought resistance inoculated with TY29 and TY35 were better than those of the others.