Abstract: In recent years,under the comprehensive influence of climate change and human activities,the spatial and temporal distribution characteristics of the flood process in Dadu River Basin have changed. Taking Shaping Station as the representative,this paper analyzes the characteristics of the flood peak,flood volume and peak occurrence time of the previous floods in the middle and lower reaches of Dadu River from 1937 to 2019,and makes a comprehensive analysis of the characteristics of the flood process,such as trend,mutation and period,by using linear regression,sliding average,wavelet decomposition,moving-T test,Mann-Kendall test and Morlet wavelet analysis. Results show that the middle and lower reaches of dadu river flood peak flow and tend to significantly reduce the time of the actual sequence,annual maximum flood peak time has obvious tendency of forward,flood peak,the mutation of the actual time mainly concentrated in the 1950s and 1960s,the peak time now there was no significant mutation of the year,five evaluation index of the first main flood process cycle for 24 years.