Compared with the common canalization project，there are some technical problems of dam site selection，such as the connection of the lowest navigable water level between the hydro-junction and the analysis of the impact on the power generation of the built hydro-power station，when the dam site is added to the existing channelization cascades.The research cases are few.Taking the dam site selection of Shuidongba navigation hydro-junction project in the Jialing River as an example，we analyze advantages and disadvantages of conditions of water depth，river regime，topography and geology，and submergence loss of the section of the reservoir tail，put forward ideas of preliminary selection of dam site，layout of key buildings and determination of normal water level of key project，and carry out the comprehensive dam site selection from the aspects of water level connection，reservoir landscape，influence on power generation of built power stations，construction diversion and project investment，etc.The conclusion is that the dam site of Fuxingchang is recommended as the dam site of Shuidongba navigation hydro-junction.