Abstract:Based on the method combining statistical analysis with the compilation of historical archives,this article makes an investigation of the temporal and scale properties of flood disasters that occurred in the Guanzhong reach of Weihe River during the last 400 years. According to the related historical archives,99 flood events were recorded during the period,with an approximate frequency of 4 years. 52 of these floods are classified into small-scale flood,35 into medium-scale flood,8 into large flood,and 4 into catastrophic flood. Three main flood sub-periods are also distinguished. The period from 1600 to 1669 and the period from 1670 to 1859 were characterized by low-frequency floods,with a rising and a relatively level tendency,respectively,while the period from 1860 to 1995,by high frequency floods. Periodical analysis indicates that quasi 3-year is a most prominent cycle and 7.14-year,a secondary cycle,which are supposed to correspond to the 2~7 year cycle of ENSO.