Abstract: Low flow and flood are extreme hydrology,but researching profundity of low flow is lower than that of flood.This paper summarizes mostly contents and methods about the research of low flow at home and abroad,including three contents: (1) analysis on factors that influence the runoff of low flow,(2) frequency analysis and the methods dealing with zero of low flow,and (3) calculating and forecasting of low flow system.Then this paper puts forward some foreland researching contents in the domain of low flow,discusses about traditional methods of probability statistics and time-sequence analysis,and emphasizes new technique,"3S"(RS,GIS,GPS) technology,in applications of low flow at the present time.This paper provides important referent worthiness for more researching low flow in the future.