Abstract:Using the daily precipitation and daily runoff data in the songhua river basin during 1961~2018, based on the 11 extreme precipitation index and five extreme runoff indicators, taking the trend analysis method, Mann-Kendall nonparametric test methods, Mann-Kendall mutation test, kriging interpolation method, Pearson correlation coefficient and other methods, this paper analyzed the change characteristics and regional differences of extreme precipitation and extreme runoff events in songhua river basin and, at the same time, analyzed the correlation between the extreme precipitation and extreme runoff events. The results show that, except the CDD and SDII indexes in the continuous dry period, the perennial average values of the other indexes all show that the songhua River basin is the high-value region, the songhua River main stream basin is the second-highest value region, and the Nenjiang River basin is the low-value region. The spatial trend distribution and abrupt transition years of each extreme precipitation index also reflect regional differences. The variation trend of each extreme runoff index was similar to that of the abrupt change year, and all showed a slight variation trend. Under different time scales, the correlation coefficients of extreme precipitation and extreme runoff events all passed the 99% significance test. Due to the slow confluence of the Songhua River Basin, extreme precipitation and extreme runoff events show the most significant correlation when the time scale is 30 days.