Abstract: The river ecological hydrological situation plays a decisive role in the ecosystem, to evaluate quantitatively the influence of ecological and hydrological situation of daily Regulating power station reservoir area, it can provide scientific and technological support for the ecological operation of power stations and the maintenance of the ecological health of rivers. In this paper, variation range method (RVA) was used to analyze the daily flow rate, water level and flow velocity indicators of Hengyang hydrological station in Dayuandu junction reservoir area of Xiangjiang river main stream from 1959 to 2015, and the change of biodiversity in the reservoir area was preliminarily evaluated by the biodiversity index SI. The results show that after daily regulation of water storage in the power station, the characteristics and ecological influence of the ecological and hydrological changes in the reservoir area are as follows: The overall change degree of flow rate IHA index reached 81%, and the overall change degree of flow velocity IHA index reached 43%; In 4-7 month, the monthly average flow velocity decreased (height changed), which was not conducive to the spawning activities of “The four major Chinese carps”; The increase of annual minimum flow in the reservoir area is beneficial to the protection of natural habitats and plant communities; The decrease of annual extreme flow velocity increases the risk of ecological environment while changing the river landform in the reservoir area; The minimum annual value of flow rate and flow velocity changes by 100%, affecting the life activities of organisms; The changes of low flow rate pulse duration and high flow velocity pulse duration are not conducive to stimulate spawning and reproduction of domestic fish, After impoundment, SI value and biodiversity decreased.