The frequent occurrence of flood disasters in Poyang Lake has brought serious threat and impact to people's life,property safety,economic and social development.Therefore,based on the water level data of Xingzi hydrological station of Poyang Lake from 1951 to 2020,this paper uses the linear regression analysis method,Mann-Kendall trend test method and Pettitt mutation point test method to analyze the trend and mutation of flood elements in Poyang Lake.The results show that:（1）the annual maximum water level shows an upward trend on the whole,and no obvious trend is detected,but the local change trend is obvious.There is an obvious upward trend from 2001 to 2020,the time of annual maximum water level does not have an obvious change trend,the duration of over alert water level has an obvious upward trend,and the flood risk degree of Poyang Lake has an upward trend in recent years;（2）There is no significant mutation in the annual maximum water level,the occurrence time of annual maximum water level and the duration of exceeding warning water level;（3）The impact of climate change on flood factors of Poyang Lake is dominant,and the impact of human activities is relatively small.The study on the evolution of flood elements and its influencing factors in Poyang Lake has a certain reference value for flood control and disaster reduction in Poyang Lake region.