[Objective] The flood information recorded in floodplain sediments during the historical period was analyzed in order to reveal the extreme flood events and the regularity of flood occurrence, and to provide guidance for flood control and disaster reduction. [Methods] Particle size characteristics and flood events for the floodplain profile of Hengyang Reach of the Xiangjiang River in Hu’nan Province were studied based on particle size analysis of 91 samples from the flood plain combined with AMS ¹⁴C dating. [Results] ① The composition of floodplain sediments mainly included coarse silt, coarse sand, and fine sand. The grain size parameters showed that the profile flood sedimentary power was strong, the sorting coefficient was excellent, and the wide peak was in majority; ② The flood scale of the five flood stages of the Jixiang profile followed the order of stage B>stage D>stage A>stage C>stage E. In addition, between 34—40, 44—46 cm in stage B, and between 130 and 134 cm in stage D, the content of coarse sand increased abnormally, the content of coarse silt and fine silt was very small, and the median partilce size value was in the lowest range. Flood sedimentary power was extremely strong. The flood events were all in periods when Hengyang catastrophic flood events occurred; ③ The median particle size values were positively correlated with the average particle size values and the content of coarse silt + fine silt. There was a significant negative correlation between the content of coarse sand and average particle size values, the median particle size values, and the content of coarse silt + fine silt. [Conclusion] The flood scale of the Hengyang reach has, on the whole, shown an increasing trend since 6 390 B P Both sedimentary stage A and stage B are flood prone periods. The four indicators (content of coarse sand, average particle size values, median particle size values, and content of coarse silt + fine silt) could well identify flood events.