Abstract: Available water resources is the possible consumed water resources for outer rivevvay in a river basin from the point of view of water resources utilization.It has a practice significance to control the degree of water resources development and utilizatio n,study water resources rational allocation and water resources carrying capacity.Start with setting the concept of available water resources,this paper puts forward the calculation matheds for available surface water resources and total available water resources,the total available water resources in China and in the first rank areas are estimated by using the methods, and the degree,the limit and the potential of the development and utilization of water resources in China are analyzed.