Abstract: Base-flow is the base river runoff supplied by groundwater.With features of sustaining a stable ecological system,exact calculation of base-flow is of important significance in eco-environmental problems of river cut off,land subsidence,shrinkage of lakes,degradation of vegetation,and so on.The focus of this paper is on the definition of base-flow,research importance,types of calculation methods,evaluation of application scope and prior developmental direction of these methods.The calculation ty...