Currently,the protection of fish resources in Minjiang River is imminent.Although the traditional fishing rules and policies have improved passive fishery management,it is difficult to mobilize enterprises to take the initiative in fishery protection.The “ten-year fishing ban” provides an opportunity to promote the green cycle of fishery development.Based on the data from the Longxikou Cascade Navigation-power Junction,this paper takes “ensuring the prosperity of fish”,an important way of green ecological construction of navigation-power junctions in mountainous rivers,as the core.The paper also adopts a mixed-method approach to explore fish protection behavior in the context of vigorous hydropower development.It is found that the practice of “ensuring the prosperity of fish” can significantly improve the green ecological level of the project.The mechanism of action shows that the Longxikou Cascade Navigation-power Junction effectively enhances the sustainable use and ecological health of fish resources through mitigation measures and ecological engineering.This paper analyzes the impacts of the Longxikou Cascade Navigation-power Junction on fish resources and protection measures,so as to provide a new incentive factor for the green ecological construction of enterprises.