Abstract: In order to analyse the hydrological variation characteristics of Cuntan station in dry period (November to April) after the operation of the cascade reservoirs, This study use the Indicators of Hydrologic Alteration and Range of Variability Approach (IHA/RVA) method to analyse the hydrological variation characteristics of the daily average flow series of Cuntan station from 1954 to 2021, and analyzed the trend of the IHA indicators by the Rescaled Range (R/S) method. The results as follows: (1） There are 11 indicators had height changes, 4 indicators had moderate changes, 9 indicators had low changes, mainly reflected in the increasing of the average monthly flow and minimum flow in dry period, the initial maximum flow occurrence time shrinks from 1-22 th November to 1-8 th November, the minimum flow occurrence times advanced nearly 20 days, and the flow reversal times increased. (2) All the trends of IHA indicators reflected in the unbiased random walk and mean-recoverting process before influenced by the reservoirs, but 9 indicators changed to biased walk after reservoirs operation. (3） In the future, the flow in January and February, the minimum 30 day flow and the flow reversal times will continue to increase, the maximum and minimum flow occurrence times will be the trend of mean-reverting process in dry period.