Water level pays the key role on the ecosystem function in lacustrine wetland.Extreme water level，water level persistent period，rising and falling period was analyzed based on average daily water level in Poyang Lake wetlands.Extreme high water level decreased，extreme low water level and extreme interval of water level were no obvious change.Days of water level more than 16.00 m decreased，however，days of water level less than 8.00 m，10.00 m and 12.00 m increased，furthermore，low water level persistent existed.Days of water level rising was no obvious change，days of water level falling decreased，especially，days of water level falling to 10.00 m decreased obviously since 2000.Water level change was obvious from 1954 to 2016 in Poyang Lake wetlands；water level change was more and more severe since 2000 especially.Severe water level change leaded to ecosystem change，it was necessary to pay close attention to Poyang Lake wetlands for people.The result will help to deep research on the ecosystem of Poyang Lake wetlands.