Abstract: T his study aims to develop a multi‐metric, fish‐based Index of Biological Integrity (IBI) for assessing the environmental quality of rivers in Hechi Prefecture, Guangxi Province, South China. Data on fish assemblage were collected via electrofishing We screened 21 candidate metrics representing attributes of fish assemblage. Among these, six metrics were finally selected for the IBI. It was shown that the fish-based biological integrity was good in Xiaohuanjiang River , fair in Hongshuihe, Longjiang and Dahuanjiang Rivers, but poor in Diaojiang River. The results of assessment were consistent with the actual situation of human disturbance. The assessment system constructed by this study could be used or used for reference in the area around Hechi. Biotic integrity assessment was an important means of water environment quality monitoring. To enable the biotic integrity assessment more scientific and more objective, much more research work is required to focus on the relationship between biotic integrity and environmental factors.