Research on the health of Weihe River based on AHP fuzzy comprehensive evaluation

River health assessment provides a foundation for the sustainable development of rivers. As a first-class tributary of the Yellow River, the ecological health of Weihe River is of great significance for the high-quality development of the Yellow River. In order to comprehensively evaluate the health status of Weihe River Basin, the ecological health evaluation criteria of Weihe River Basin were established by selecting 3 criteria and 11 indicators, including physical habitat status, water quality status and aquatic organisms status. The weights were determined by AHP, and the Weihe River Basin was evaluated by multi-level fuzzy evaluation combined with the principle of maximum membership. The results show that 8 of the 25 points are in a healthy level; 13 were at sub-healthy level; 4 of them are in unhealthy level, and the comprehensive health evaluation result of Weihe River is sub-healthy. The ecological health status of the Weihe River headwaters, Baoji section to Xi’an section is good, while the ecological health of Tianshui—Baoji section and downstream section is poor, and the unhealthy points are mainly concentrated in the downstream, showing significant spatial differences. The evaluation results of physical habitat, water quality and aquatic organisms are sub-healthy, healthy and sub-healthy, respectively. Physical habitat and aquatic organisms are the key factors affecting the health of river ecosystem, which are mainly affected by human activities and natural environment. It needs to take relevant measures to restore the ecological health of Weihe River.