Beginning with a discussion on the concept of the flow unit, this paper, based on the authors’ experience acquired in practice, deals in detail with the methods for the study of flow unit, such as sedimentological and sequence stratigraphic theories, cluster analysis, geological modeling, physical experiment, logging and seismic physical geography. The merits and shortcomings of these methods are evaluated, and the existing problems in the flow unit study are analyzed. On such a basis, the development tendency of the flow unit study is pointed out.