Abstract: The authors come to conclusions that the main problems obstructing the development of these theories are an open system and initial conditionds, and that the river system in study must be considered as to be an open system , and different initial conditions correspond to different theories(maximum and minimum energy dissipation theories). Last, the authors analyse emphatically the new research fruits of these theories since 1990s, and point out that the effect of sediment on evolution process of river should be taken into account to make the formulas more physical meaning.