Abstract: The insufficiency of water source has become the main limiting factor of agricultural development in Cangzhou District, Hebei province. Due to the overexploiting of underground water and Iess rainfall year after year that makes the underground water-table lowering greatly. The contradiction between supply and demand of underground water becomes very serious. As a great amount of annual precipitation concentrated in summer, the paper suggests to store the rain during the summer time in order to regulate the soil water content, complement the shallow underground layer water and protect the deep underground layer water source.The paper systematically analysed and proved that the development of storing water in a plain is feasible. The paper also determined the index of storing water on the basis of different underground water-table and diffenrdent rainfall. It will provide the scientific basis for storing water in a plain topography. The paper introduces the benefits of storing water both by engineering and agricultural means by experiments done by the authors. At last, the paper presents some suggestions on the construction of the water storage engineering in a plain.