The Hanjiang River is the biggest tributary of the Yangtze River and it will supply water resource to Beijing through the national “South-to-North Water Diversion Project”. Paleohydrological investigation was carried out in the upper Hanjiang River valley in the last years. Typical palaeoflood slackwater deposit was identified along the riverbanks in the Ankang East reach by using the sedimentary criteria. Sediment samples and OSL dating samples were taken during our fieldwork. The results of laboratory analysis including grain-size distribution and magnetic susceptibility indicate that these bedded palaeoflood SWD were deposited by the suspended sediment load in floodwater. They have therefore recorded the palaeoflood events occurred in the Ankang East reach in the upper reaches of the Hanjiang River. OSL dating for the quarts grains at a size range of 40-63 μm separated from the samples by using the single aliquot regenerative-dose（SAR）protocol. All OSL measurements were made on a Risø TL/OSL DA-20 dating system using a blue light (470 nm) for optical stimulation. The dose rates were converted by using the measured concentrations of U, Th, K elements and calibrated. The OSL dates were figured out by using the Age.exe software written by Grün (2003). The chronology framework of palaeoflood events were reconstructed by using the OSL dates and a stratigraphic correlation with the previously dated sites. The results show that the palaeoflood events represented by SWD1 occurred during 13.15－12.27 ka. This well correlated to the climatic transition from the BL+AL stage to the Younger Dryas Event (YD). The palaeoflood events recorded by SWD2 were dated to 1000-900 a. It corresponds to the late period of the North Song Dynasty（A.D. 1100-1000）which is also a time of climatic decline. These results and the climatic records from the upper Hanjiang river valley and various regions within China indicate that the occurrence of palaeoflood events is related closely to the change in monsoonal climate. The extraordinary rainstorms and floods often occurred during the abrupt climatic event, climatic decline, and climatic transition. highly unstable climate may result in great variation of precipitation，which may cause floods and droughts. These results are of great importance in understanding the regional hydrological response to global climatic change. They are also important in utilization of water resources, in hydraulic engineering, and in flood control and disaster reduction.