Using the water resource data from 1994 to 2000 year and the result of the first national water resource evaluation to analyze the water resource distribution and the rule of water resource evolvement in recent 50 years of arid and semi arid regions in north China by statistical method. The identical relation of precipitation and water resource distribution is quantificationally explained of arid and semi arid regions,evaluating the exploitation and utilization present situation of water resource and the balance of water supply and requirement provide reference for optimal configuring water resource,regulating and optimizing agriculture structure and rational exploiting and utilizing the groundwater resource.