Taipingzhou shortcut waterway lies to the right branch of Taipingzhou in the lower Yangtze and it belongs to a typical tidal reach.The left branch of Taipingzhou is the main navigation channel,and the 12.5 meter Deep Waterway Project in the Yangtze Estuary to be implemented in the near future.During regulation engineering of Taipingzhou reach，we need to fully recognize its impact on the main river，and take relevant countermeasures.This paper establishes an unsteady 2-D shallow water flow tidal sediment mathematical model for the Yangzhong reaches and analyzes the impacts of Taipingzhou reach regulation engineering on the river bed evolution of the main river.