Abstract: Under the action of impoundment and regulation of large water conservancy projects, especially reservoirs, the incoming flow and sediment conditions of the downstream channel change remarkably, which will lead to unbalanced sediment transport in the channel, and induce scouring and remaking of the riverbed. The riverbed scour and remaking process in the downstream channel of water conservancy project is characterized by the coupling of multiple processes (inclusive of sediment scour, coarsening, exchange and suspended sediment recovery) and the macroscopic morphological changes of multi-scale complex responses (such as sediment scouring and silting, bed surface morphological changes, longitudinal slope changes, as well as river pattern and river regime adjustment). The related researches in China and abroad are mainly carried out from two aspects, namely, microscopic mechanism and macroscopic law, by means of field measurement data analysis, theoretical research, physical model test and numerical simulation. In this paper the research results of river bed scour and remaking process in the downstream of water conservancy projects in China and abroad are summarized; the research progress of key technologies in physical model test and numerical simulation of river bed scour and remaking are expounded; and the key points for further research and the scientific and technological problems to be solved are presented.

Key words: river channel downstream of reservoir, river bed scouring, sediment transport features, riverbed remaking, movable bank simulation, recovery saturation coefficient, research progress