Abstract: In construction projects, EPC is a method widely used at home and abroad, but it is not widely used in the construction of water conservancy and hydropower megaprojects in China. Based on the analysis of the construction characteristics of water conservancy and hydropower megaprojects and the development of China’s hydropower construction market, the main issues of EPC project transaction governance structure are optimized, including the use of the “total price” pricing method for the project as a whole, but for some sub-projects with large uncertainty of “site data”, the pricing method with risk allocation is adopted to motivate the contractor to optimize the project. And the general contractor of the project is required to build a tight consortium, namely cooperative enterprise, so that the project design and construction can be deeply integrated to fully exploit the potential of market entities and give full play to the advantages of the general contracting transaction method. The effectiveness of the above optimization methods are demonstrated by two work cases.