In order to evaluate the effectiveness of ecological flow support and the adaptability of ecological flow target, the response relationship between the flow factor and the biological factor was constructed based on the sampling data of benthos in Taoer River. The results show that under the current ecological flow target, which is settled as 5%, 10%, 15% of the annual average runoff for frozen, normal, and wet period, the compliance rate of ecological flow improved gradually in temporal. And the compliance rate of ecological flow decreased from upstream to downstream in spatial, which like the change trend of benthic diversity and biomass. Then, the Pearson analysis showed that the correlation between the benthic diversity index and the compliance rate of ecological discharge is the most significant and the linear regression relationship was established accordingly. Finally, combined with the regression relationship and scenario analysis, it was found that the linear fitting degree was the highest (R²=0.998) when the targets of the frozen,normal,and wet periods were setting as 7%,14%, and 27%, respectively, indicating that the target was most suitable with the best effect on maintaining benthic diversity. Thus, it is suggested to gradually increase the ecological flow target and promote the restoration of damaged ecosystem in Taoer River.