Abstract: Water level is the key index of hydrological situation and ecosystem health of lake wetland. How to determine the appropriate ecological water level threshold is the key to ensure the health of lake wetland. In this paper, the suitable ecological water level process of East Dongting Lake was established by means of RVA method, dynamic calculation method and mathematical statistics, taking the pre-abrupt water level process of Chenglingji station and Lujiao Station (daily water level data from 1959 to 1978) as the reference period. Research results show that: (1) the RVA method to calculate monthly average range of ecological water level threshold is 2.18 m, and the dynamic calculation method for calculating the ecological water level threshold range from month to month average is 5.12 m, the water level fluctuation is bigger, for East Dongting lake is suitable for ecological water level, RVA method to calculate the range of ecological water level is more advantageous to maintain health and biodiversity of wetland plant communities. (2) Affected by the elevation of the lake bottom, the occurrence time of high and low water level in Lujiao Station is about 15 days earlier than that in Chenglingji Station. However, there is no significant difference between the duration and fluctuation range of high and low water level and the average change rate of high and low water level in the sensitive period of fish and plants (March-June). (3) After the variation of water level (2003-2016), the water level of East Dongting Lake was within the ecological water level threshold for most of the time, and only adjustment measures should be taken for the declining period that did not meet the ecological water level. The difference of the average annual water level between Lujiao Station and Chenglingji Station was reduced by 0.46 m, and the hydrodynamic system of Dongting Lake was weakened. The research can provide the basis for the ecological water level of East Dongting Lake and the joint operation of three Gorges and upstream power stations.