Based on the daily discharge and meteorological date from 1972 to 2012 at the Dashankou hydrological station and Bayinbuluke weather station in the Kaidu River Basin,the characteristics of extreme hydrological events(EHE)were investigated,the threshold value was determined by the cumulative frequency method,the inner-annual and inter-annual changes of EHE,the session distribution of EHE and their responses to climate change were analyzed in the study area.The results showed that the EHE in the region was extremely unstable.The inner-annual distribution was uneven and the concentration degree was higher.The extreme flood events mainly occurred in July,and the extreme low water events mainly appeared in February.The inter-annual variability was quite unstable with a high deviation from the normal distribution.The extreme flood events totally presented an increasing trend and had an abrupt change in 1986;while the extreme low water events totally presented a decreasing trend and had an abrupt change in 1993.The extreme flood frequency had a higher correlation with precipitation,while the extreme low water frequency had a higher negative correlation with temperature.