Abstract: Accurate assessment of regional flood risks and effective mitigation of flood-induced losses are crucial for ensuring sustainable development in river basins. Firstly, the hydrologic and hydrodynamic coupling model was comprehensively used to calculate the changes of river flow under different engineering conditions. Secondly, the flood evaluation indicator system was constructed from three dimensions of disaster bearing body toughness, disaster bearing body exposure and flood probability. Finally, the flood risk degree of Yiluo River basin under different engineering conditions was analyzed by using the game theory combination weighting method and the improved multi-attribute boundary area comparison model. The results show that the indicators of maximum discharge of the nearest river system, population density and slope had the greatest influence on flood risk. The flood risk level in Yiluo River Basin presented a spatial pattern of “low in the west and high in the east”. Under baseline conditions without considering water conservancy projects, Shangluo, Sanmenxia, and Weinan exhibited low flood risk levels, while Zhengzhou and Luoyang were classified as medium-risk areas. However, when accounting for the mitigating effects of water conservancy projects, all cities in the basin showed reduced risk levels, with the high-risk zones in the eastern region decreasing by approximately 35%. This study highlights the importance of incorporating water conservancy projects impacts in flood risk assessments, providing a scientific basis for refined and dynamic flood management strategies.