AbstractThis study investigates characteristics and patterns of insect species diversity on the Ordos Plateau , a special ecotone with ext remely arid environment s in Northwest China. Using pitfall t raps , we collected 5159 insect specimen and 291 other invertebrates. As the most dominant group , beetles accounted for 45. 8 %of the total collected insect s , and among beetles , 92. 8 %of individuals are Tenebrionidae and Carabidae. Plotting the log values of individual numbers of different beetle species , from high to low , result s in patterns that separate the four investigated sites into two groups. One includes Hangjinqi , with mainly desert shrub environment s , and Shihuimiao with a variety of habitat s of different vegetation. The other includes Shilongmiao and Xinjiezhen with different environment s , frequently artificial regeneration. The former exhibit s high species diversity and richness , whereas the latter exhibit s high evenness. Principal Component Analysis (PCA) ordination of beetle communities indicates that the species dist ribution was determined by precipitation gradient and vegetation types. A positive correlation is seen between precipitation and beetle species diversity and evenness , while a negative correlation is one exhibited between precipitation and individual numbers. Species richness does not show such patterns. Thus , in an arid region as the Ordos Plateau , special insect species and their natural communities can be preserved only when the original vegetation is well protected and the disturbances of human activity are effectively limited. The environment s in this region can be improved and a high insect diversity can be developed when regeneration is increased and drift sanddune is decreased in most part s of this region.