Abstract: The low-water level at Yichang Station is an important factor affecting the normal navigation on the river reaches below the Three Gorges Dam.Based on the measured results，this paper analyzed the variation trend and influencing factors of the low-water levels corresponding to the discharge flow 6000m3/s at Yichang Station from 1950 to 2021.The analysis results shows that the low-water levels at Yichang Station had experienced the process of fluctuation，decline，mutation，again decline and then stabilization successively since the 1950s.And the change pattern had obvious phase characteristics.It was concluded that the change of channel erosion and deposition，and the erosion basis were the determining mechanism of rise，decline and stability of low-water levels at Yichang Station.There were also lots of influencing factors that affected the changes of these mechanisms，such as the bend cutting and straightening of the downstream Jingjiang River reach，the construction and operation of Gezhouba Project，the building aggregate mining and channel sand mining，channel maintenance and dredging，riverbed evolution in special year of water and sand，the construction and operation of Three Gorges Project，joint operation of upstream cascade reservoir，and the implementation of river regulation and protection projects.However，there were different factors that led the changes in different phases of the low-water levels change at Yichang Station.