Hydrological and geomorphological investigations were carried out in the upper reaches of the Yellow River. Typical palaeoflood slackwater deposit beds of the Holocene period were found at the JPC and YPC site in the Jingyuan-Jingtai gorge. The palaeoflood peak stages were estimated with elevations and deposition depths of the SWD. The results indicated palaeoflood discharges were estimated between 15 110 and 17 740m3/s using the HEC-RAS one dimensional model running with the ArcView environment. A sensitivity test performed on the model indicated that for a 25% variation in roughness values,an error between -10.6% and 5.5% was introduced in the results for peak discharge. Based on flood stage indicators,peak discharge of the 2012 flood was reconstructed in the same reach using the HEC-RAS model and the same hydraulic parameters. The error between the reconstructed and gauged peak flood discharges is 2.7%. These show that the results reconstructed by the HEC-RAS model are reliable. The reconstructed peak discharge of the palaeoflood are about twice the gauged largest floods in the upper Yellow River reach. The flood data series for the river were extended to a 10,000-year time-scale. Stratigraphic correlation and OSL dating shows that extreme palaeofloods were dated to 3 200~3 000 years ago at the turn of the termination of middle Holocene and the initiation of the late Holocene,during the monsoonal shift in the East Asia. The hydrological system experienced abrupt change under the climatic background. Extreme palaeoflood events were documented not only in the upper Yellow River reaches,but also in the middle reaches and other tributaries of the Yellow River. These findings are of significance in understanding interactions between hydrological systems and climatic change in arid and semi-arid regions in China.