Abstract: The evaluation of fish index of biotic integrity (F-IBI) is an important basis for ecosystem health assessment, and it is also a prerequisite for ecological restoration. In order to explore the impact on fish resources and habitats in the projectaffected area by the human disturbance, the study constructed a evaluation system ofF-IBI based on the 2020-2021 fish resources survey and historical data, and then evaluated the status of F-IBI and the degree of coercion.In general, the F-IBI has not change muchin the projectaffected area before and after the operation of Datengxia Project, and the evaluation grades were all at the "general" level.However, compared with historical data, the number of rare and endemic fish species has decreased significantly and the number of alien species has increased of the current survey; and then, the F-IBI in the reaches of the reservoir and typical tributarywere better than that of the reservoir area and the lower reaches of the dam. So, it’s necessary to Long-term evaluate the changes of F-IBI, for identify the ecological impact caused by Datangxia Project and the effect of ecological protection measures. Meanwhile, we should implement some measures such as habitat restoration, ecological scheduling and alien species prevention and control, to improve the level of ecological health.