Abstract: In this paper,analysis mas made of the diversity of shrubs and important herbs in arid valleys of the Bailong River in Gansu Province. The feature of changes in α diversity with elevation increasing showed that both diversity and richness indexes of shrubs slightly increased at first, then decreased and rose in the end, while evenness and dominance indexes changed little. Changes in the indexes of herbs and shrubs were similar,at the same altitude the diversity of shrub was always greater than that of herbs; Analyzing the diversity of different slopes indicated concave > flat > convex in the same shrub and herb layer. However in different aspects, the diversity of shrubs displayed shady shrub > semi-shady slope > sunny,and the diversity of herbs displayed semi-shady slope > shady > sunny. The diversity of the shrub was always greater than herbs' diversity. Thus,It could be concluded that in the arid valley of the Bailong River shrubs were dominated ecosystems.