The current range of variability approach(RVA)usually ignores the low and moderate variation index, and is difficult to distinguish the relative importance between different indicators when evaluating the overall hydrological regime of a river. Therefore, according to the response analysis of indicators of hydrological variation(IHA)including 33 hydrological indexes from 5 sorts to ecological system, this study improved the RVA approach based on projection pursuit clustering model, which is called PP-RVA and can be used for the effective analysis of river hydrological variation degree. Then, on the basis of runoff data before and after the construction of the Liujiaping Hydropower Station in Hunan Province, the hydrological situation was evaluated by the proposed PP-RAV approach. From the comparison, the overall variability is 83. 21%, which belongs to a high variability. The average flow, high flow rate and 7-day minimum flow in May have the greatest influence on the hydrological regime. The evaluating results fit the overall information of river and distribution characteristics of change degree of index corresponded with the objective reality. Moreover, this study indicates that the current operation mode of Liujiaping Hydropower Station has influenced the ecological system of lower reaches. Therefore, it is urgent to carry out the ecological operation practice to realize the coordinated development of regional economy and ecological environment.