The navigation and power junction project generally faces some problems such as large investment，strong public welfare and poor economic benefits. In order to improve the economic benefits of the project，the owner unit must strictly control the investment cost of the project from all angles to achieve the purpose of reducing costs and increasing efficiency. We take Qianwei navigation and power junction in the Minjiang River comprehensive development project as an example，start from the four aspects of engineering design optimization，contract management，fund management and tax planning，expound in detail the main measures taken by the project to control the investment cost of the project and the effects. The results show that every management mean plays an important role in the process of project investment cost control，which can lay a solid foundation for the good operation.