The eastern Lake Dongting wetland is of great importance worldwide.It has been suffered from progressive degradation lately.Wetland ecosystem is considered to be adapted to hydrological sequence before alteration caused by climate changes and human related activities.Average monthly water-level of three hydrological stations in the Lake Dongting region were analyzed in this study to obtain ecological water-level.The point of the highest T statistic value calculated by moving T-test method was considered to be the alteration point.The sequence was then divided into two parts.The subsequence before alteration point was used to find the most fitted probability distribution function.The ecological water-level was considered to be the average monthly water-level of the highest probability of the probability distribution function.The results indicate that average monthly water-level has been alternated, and the ecological water-level determined in this paper is reasonable and can provide some guides to the restoration of the Lake Dongting wetland.