In this study, the hydrological trend of the Huangjiagang hydro-station downstream of Danjiangkou from 1965 to 2017 was evaluated by RVA method via dividing different influence periods. The results show that the impoundment of the Danjiangkou Dam can increase the discharge in dry seasons while decrease the discharge in flood and normal seasons in the downstream. The decrease of rainfall caused by climate change leads to the decrease of the monthly mean flow and the annual maximum discharge, but the occurrence of low flow pulse is increased. The backwater of the cascade dams increases the monthly mean flow and the annual minimum discharge with earlier occurrence. The Middle Route of the South-to-North Water Transfer Project substantially reduces the monthly mean flow and the annual minimum discharge with an increase of both low and high flow pulse. The hydrological regime fluctuation in the middle and lower reaches of the Hanjiang River is induced by the different influencing periods, which affects the stability of aquatic ecosystems.