Abstract: To understand the Horqin Sandy common Mongolian medicinal plant resources and the colonization characteristics of arbuscular mycorrhizal fungi（Arbuscular Mycorrhizal Fungi, AMF）, we investigated Mongolian medicinal plant resources and AMF colonization in several common medicinal plants in the hinterland of Horqin sandy in Aung Nai rural territory of Naiman Banner in June and September, 2005. In this study, we collected 28 Mongolian medicinal plants, belonging to14 families and 23 genera, from the Horqin Sandy land, which of the most were compositae species（32.1%）. The medicinal parts had 8 types, including the whole plant, aerial parts, roots, stems, leaves, flowers, seeds and fruits, of which the largest was whole plant, involving 15 species（53.6%）. Among Mongolian medicinal plants, there were 25 kinds of AM mycorrhizal plants（89.3%）, the majority of surveyed medicinal mycorrhizal plants form a mycelium structure（78.6%）, and the vesicular structures（28.6%） and arbuscular structures（10.7%） was little. The study of the Mongolian medicinal plant resources and their AMF colonization characteristic of Horqin sandy would conduct a rational use of Mongolian medicinal plant resources and the mycology basis in planting and the sustainable use of Mongolian medicine.