To analyze the impacts of Three Gorges-gezhouba cascade reservoirs on the sediment regime in the Yangtze River downstream, two hydrological stations Cuntan and Yichang which were respectively located in the upstream and downstream of Three Gorges-gezhouba cascade reservoirs were selected as study sites. The whole study period was divided into several sub-periods according to the different phases of construction and operation of Gezhouba and Three Gorges Reservoirs. On the basis of the long time series of daily water discharge and sediment concentration from Cuntan and Yichang from 1954 to 2012, the impacts of Three Gorges-gezhouba cascade reservoirs to the downstream sediment regime in annual, monthly and daily scales were investigated respectively. The results revealed: the Three Gorges-gezhouba cascade reservoirs have influences on annual, monthly and daily sediment regime, which varied according to reservoir storage capacity and operation phase. The impacts are more significant when the storage is bigger and the storage level is higher. The study is intended to provide references for the assessment of impacts of dam operation on the health and stability of the Yangtze River ecosystem.