Drought is a world-spread problem seriously influencing production and quality of plants. At the same time, drought is one of the most important environmental factors limiting growth and development of desert plants in Northwest China. It is well known that Arbuscular mycorrhizal fungi (AMF) can enhance the ability of the plants to establish and cope with stressful situations, such as drought stress, salt stress, nutrient deficiency, etc. Almost eighty percent of land plant species on the earth can form symbiotic associations with AMF. With pot experiment in a greenhouse, the paper studied the effects of arbuscular mycorrhizal fungi (Glomus mosseae)on the drought tolerance of Seriphidium. minchnense (S. minchnense) under water stress. Seeds were collected from natural growth environment of S. minchnense in Minqin County and sown in training matrix with sandy: soil (2 ∶ 1, mass ratio). Seedlings with similar height and crown were selected and divided into three groups (6 pots per group) when they had 2-3 leaves. The soil relative water content of three groups was severe stress (20% of maximum field capacity), moderate stress (40% of maximum field capacity), and normal water (60% of maximum field capacity), respectively. Each group of S. minchnense seedlings was inoculated with AM fungi Glomus mosseae (3 pots), and non-mycorrhizal inoculation (3 pots), namely control (CK), respectively. The results showed that inoculation with AM fungi significantly increased the biomass accumulation and infection rate of S. minchnense seedlings. The total phosphor (P) content of shoot and root of seedlings were significantly increased under different water treatments, and total flavonoids content of shoot was only significantly increased under severe stress, while branch number and total N content of shoot and root were not significantly affected under incolation AM fungi. Mycorrhizal dependency and contribution rate of total nitrogen (N) and total P under water stress were higher than that under normal water condition. The content of leaf relative water, soluble protein, chlorophyll, total N and total P were significantly improved in different stages, and total flavonoids content of leaf was significantly increased just under severe stress, while the proline content was decreased throughout the growth period by colonization AM fungi. The content of soluble sugar in leaves of inoculated plant was significantly lower than that of non-inoculated plants in early stage, and significantly higher than that of non-inoculated plant in middle and latter stages. It could be concluded that the mechanism of AM fungi enhancing plant growth and strengthening the drought resistance of host plants may be the direct role of AM fungal hyphal contribution to soil water and minerals uptake in mycorrhizal plant, and the indirect role of AM fungi improves the physiological metabolic activity of host plants.