Through the field investigation in the upper reaches of Hanjiang River, 4modern flood level marks after 1983were found on housing walls in Jiahe and Yangwei Towns of Baihe County. The ages of the 4flood level marks were determined accurately through local interview and consulting data.Then their peak dischar-ges were quantitatively figured out by the hydrology principle of slope-area method.Compared with the data observed from Baihe hydrological gauge station, the errors were found to be 0.5%～5.3% for Jiahe Town and-0.2%～5.1% for Yangwei Town. The result showed that flood level mark in river channel can be used to check peak discharge for an abrupt flood disaster under the influence of global climate change. It can not only improve the accuracy of flood discharge estimation in the river section short of hydrological data, but al-so provide the scientific data for water resources development and flood hazards mitigation.