In recent years,the measured value of channel water level in Changzhou hub downstream has shown a trend of declining,which was inconsistent with the design value of the original channel water level.An analysis for the reason of bed evolution is carried out based on the hydrological data of the channel,and the result shows that the reasons for the declining of the channel water level of Changzhou hub’s downstream lies in the influence of riverbed hubs’downstream from upstream inflow and sediment,excessive sand mining in downstream river channel,river cascade development and construction of water conservancy,as well as the construction of waterway regulation buildings,etc.Combining with the practical situation of the site,we put forward the improvement measures including controlling the excessive sand mining in the hub’s downstream river channel,taking restrictive regulation measures and strengthening detection of the river section,which provides a support for the normal navigation of Changzhou hub downstream channel.