The environmental effects of the world's largest Three Gorges Dam (TGD) have been received worldwide attentions. It is the first dynamics monitoring of mid-channel bars (MCBs) in the downstream of TGD at large spatiotemporal scale. The study shows most of the MCBs are located in the lower reach. Small MCBs become shorter and wider whereas the others became slimmer in post-TGD period. Impacts from the TGD operation on the MCB dynamics could decrease along with the increasing distance from TGD.