Abstract: Statistical analysis based on measured hydrological data indicates that there were 143 backflow events in Poyang Lake from 1951 to 2024. Utilizing the statistics of these 143 events, this paper analyzes the characteristics and patterns of backflow in Poyang Lake, reveals the changing patterns and trends of backflow over the past 70 years, and discusses the conditions leading to backflow in Poyang Lake. The analysis shows that backflow primarily occurs during July to September when the water level at Hukou is in the medium-low range of 12～16 m. Over the past 74 years, the frequency of backflow events has generally shown a decreasing trend. Specifically, the frequency exhibited an overall increasing trend from 1951 to 1970, followed by a decreasing trend from 1971 to 2010, and then a rebound(increasing) trend after 2011. The duration of backflow events has shown a shortening trend, and the timing of their occurrence has exhibited an advancing trend.