In this paper，the boundary conditions of ecological rivers are characterized into blade scale，patch scale and river scale in a perspective of multiscales.Common hydraulic and hydrodynamic issues such as solute transport，flow field characteristics and river flow capacity are preliminarily discussed.It comes to conclusion that there exists strong interactions between the eco-physical characteristics，distribution of plant mosaics and the river flow.The balance between ecological integrity and water demand should be take into full consideration in eco-river regulation.