77 soil samples and 34 soil sections from intermontane basins and alluvial plains along the Yangtze River and hilly lands in southeast Hubei were analyzed. A systematic analysis of pH and E_h values and arsenic concentration indicates that soil material is the chief factor affecting the content of As. Under the same geographical and climatic conditions, the pH and E_h values of soil seem to be the most important factors governing the vertical distribution of As. In the ore cluster areas, the soil is contaminated by As both naturally and artificially. There are many conspicuous physical and chemical differences between the two kinds of polluted soils in the vertical distribution of As content and in the pH values of soil.