Abstract: As one of the hotspots in global change research,the study of ancient floods is of great significance for regional flood prevention and mitigation.In this paper,we established a profile dating framework through 137Cs specific activity and 14C of plant residues,and analyzed the sedimentary environment indicated by the particle size characteristics of the sediments.Based on this,we discussed the indications of flood events by historical and hydrological data based on the 8.3 m high temporal resolution of floodplain sedimentary sequence in the Jingjiang River section in middle reaches of the Changjiang River.The results are as follows:(1) there are four types of particle size frequency curves in the floodplain sediments,which indicate the deposition environment from weak and stable stratospheric sediments to strong and unstable(like)bed-phase sediments,indicating the normal flood,large flood and extreme flood events respectively.(2) 13 particle size index characteristics indicate that the mean particle size,sand,(coarse silt + sand)/(fine silt + clay),median particle diameter and particle size frequency fractal dimension D are sensitive to environmental response and can well distinguish the sedimentary environment under various flood events.They detected 45 flood years recorded in the Yangzijiang profile since 1788,and the consistency with the flood years in historical and hydrological data were over 90%.The detection rates of the five indicators for flood years were 82.61%,89.12%,80.43%,71.74% and 76.09%,respectively.The results can provide a reference for floodplain sedimentary sequence in the reconstruction of high resolution flood events,and will broaden the content and connotation of the ancient flood research.