To study the influence of water resources development on ecosystem and water resources carrying capacity, the connotation, classification and evaluation methods of river connectivity are summarized, and the vertical connectivity of river is discussed in detail. From the aspects of water quality, water quantity and organism, the influence mechanism of the barrier building on the water ecosystem is analyzed. As a four-dimensional concept, that is, a time dimension and three spatial dimensions, the river connectivity affects the eco-hydrological processes, the resistance of community and the stability of the ecosystem, thus the connectivity evaluation should take into account the spatial and temporal variability. Based on analyses of current research progress, the future research directions are pointed out as follows: to further clarify the interaction between river connectivity and eco-hydrological processes from the indicated species level, to unify quantitative assessment methods and standards of the river connectivity degree to increase the comparability among different rivers or different periods for the same river, so as to provide a theoretical basis for sustainable development and protection of rivers aiming at improving the carrying capacity of water resources.