Riverbed degradation and considerable falling of water level along the downstream channel of the Changzhou hydro-junction are due to the factors of released clear water， sand mining and waterway dredging, etc. According to the measured water level and flow discharge data from Wuzhou hydrometric station， the characteristics of the water level drop and its influencing factors on the lower near-dam reaches of the Changzhou hydro-junction are analyzed. In addition，the control measures to slow down the water level drop have been investigated in the physical model tests. The design water level given by the Wuzhou hydrometric station in 2012 was approximate 1.30 m lower than the initial design value. The water level drop is mainly due to the natural evolution and sand mining during the period of 2000 to 2006. Reservior operation， waterway regulation and sand mining were the main influence factors from 2007 to 2012, however, the impact on the reservoir operation will gradually decrease. Analysis of data and model test studies show that the deep pool backfilling and construction of the spur dikes play a limited role in slowing down the water level drop; by contrast, the regulation of the hydro-junction (including raising the discharge, and increasing the diversion ratio of the outside river channel) can considerably slow down the water level drop along the lower near-dam reaches.