Abstract: The spatial distribution and highresolution morphological of riverbed micromorphology were observed using a RESON 7125 multibeam during September 2016. Bathymetric data of the Zhangjiazhou reach in 1998 and 2013 were also used to analysis the channel volume change. Results show that: (1) strong riverbed erosion was experienced in the Zhangjiazhou segment and the net erosion volume was 176×106m3 between 1998 and 2013. Several erosional holes were found in the South Zhangjiazhou Waterway which reach up to 9 m. (2) Medium grain size of the channel sediment sampled in 2016 changed from 1491 μm to 223 μm were coarser than history before 2003. (3) Approximately 829％ main channel developed dunes while 140％ of the main channel developed erosional holes. The mainly reason of the strong erosion occurred in the Zhangjiazhou segment because of the sediment supply reduced. The river channel control engineering affected the river morphology and stabilized the river regime. The water was forced by these manmade projects to return to the river trough and exacerbated the erosion phenomenon. With the sediment supply reducing in the future, the main channel of the South Zhangjiazhou Waterway may erosion further.