Ammopiptanthus mongolicus (Leguminosae) is the only endangered broadleaf evergreen shrub endemic to the deserts of northwest China, and plays a number of vital roles. A. mongolicus and its associated plants undergo competition inhibition and cooperative evolution, and are thought to be the ideal plants for use in the improvement of arid desert areas and the prevention of desertification. In this study, the symbiotic relationship between these desert plants and AM fungi was explored, along with their ecological adaptations, in order to establish a basis for vegetative restoration and ecological improvement projects involving the planting of Ammopiptanthus mongolicus. In order to elucidate the activity and ecological distribution of arbuscular mycorrhizal (AM) fungi in the desert ecosystem of northwest China, this study investigated the ecological distribution of AM fungi, and their symbioses with A. mongolicus-associated plants. We collected soil and root samples from three different sites in Dengkou, Wuhai, and Alxa, and selected two dominant A. mongolicus-associated plants from each site in the Inner Mongolian desert, in June 2013. Soil and root samples from under A. mongolicus-associated plants were collected at each site, at five depths in the soil profile:0-10, 10-20, 20-30, 30-40 cm, and 40-50 cm, and two dominant species of A. mongolicus-associated plants were collected at each site. The distribution of the AM fungi was found to be spatially heterogeneous and strongly influenced by soil characteristics. A total of 25 AM fungal species belonging to 4 genera were isolated from the soil under four A. mongolicus-associated plants:Haloxylon ammodendron, Artemisia ordosica, Caragana korshinskii, and Amygdalus mongolica. Of these fungi, 14 species belong to Glomus, 7 to Acaulospora, 3 to Funneliformis, and 1 to Scutellospora. Glomus reticulatum was the dominant fungal species, and its distribution was found to be spatially heterogeneous. Strong, spatially heterogeneous symbiotic relationships were formed between the A. mongolicus-associated plants and the AM fungi. The highest density of fungal hyphae and vesicles was found in the 10-30 cm soil layer, and the highest spore density was found in 10-20 cm soil layer. The number of AM fungal species decreased as soil depth increased. This might be due to the lower organic content and oxygen availability found in deeper soil layers, because fungi are sensitive to oxygen deprivation. Hyphal colonization was positively correlated with organic C (P<0.01) and negatively correlated with easily extractable glomain (EEG) (P<0.05). Spore density was negatively correlated with organic C and alkaline phosphatase (P<0.01), and positively correlated with available N (P<0.01). Principal component analysis showed that available P, acid phosphatase, alkalin phosphatase, and total extractable glomain (TEG) can be used to determine the nutritional status of the soil of the Inner Mongolian desert. The average TEG and EEG content of the soil was 4.76 and 1.62 mg/g, and accounted for 61.26% and 20.8% of soil organic carbon, respectively. This result indicated that glomalin was the main source of soil organic C in the Inner Mongolian desert. By comparing these results with the results of previous studies, it was determined that the total colonization and spore density of A. mongolicus is higher than that of its associated plants, which demonstrates that the AM symbiont facilitates the adaptation of A. mongolicus to this extreme desert environment. This study provides a basis for the effective use of AM fungal resources to promote the growth of host plants, and thus facilitate the vegetative restoration of desert areas.