Abstract: Water kiln in rainfed areas is a kind of catchment and conservancy project to retain rainfall so as to meet the needs of human beings, animals and irrigation. Based on physical and mechanical characters of soil in arid and semiarid areas, the principles of selective location for water kiln were introduced. Applying rock and soil stability and mechanic theories, the rational structural styles were analysized and calculation formula for controlling water kiln shape and geometric sizes were induced so as to offer references in practice.