Abstract: A comprehensive scientific research and testing platform serves as the core infrastructure driving technological innovation, with its composition and effectiveness directly affecting the level of national water security. This article seeks to systematically elucidate the logical inevitability and strategic pathways for building a comprehensive testing platform for water conservancy, hydropower, and water transport disciplines. This platform is characterized by deep integration of prototype observation, physical model testing, and mathematical model simulation (hereinafter referred to as the “three-type platform”). Historical logic demonstrates that the synergistic evolution of the “three-type platform” has been a decisive force in advancing China’s water conservancy, hydropower, and water transport engineering technologies from a phase of catching up, to running abreast, and now taking the lead in certain areas. Drawing on the 90-year practical trajectory of a national-level research institution as an example, this article argues that the synergistic evolution of the “three-type platform” is not only the cornerstone supporting the successful construction of major projects but also the fundamental driver behind the leapfrogging advancement of water conservancy engineering technologies. Theoretical logic indicates that the “three-type platform” forms a closed loop of “understanding–reproducing–predicting–optimizing” for complex hydraulic engineering systems. It serves as the methodological foundation for exploring the inherent complex laws of hydraulic systems and ensuring engineering safety. The interconnected, synergistic, and referential research within this framework ensures the scientific rigor, safety, and economic efficiency of the construction, operation, and maintenance of major projects, including “national strategic projects.” Practical logic indicates that, in the face of intertwined challenges posed by both traditional and emerging water-related issues, as well as the strategic demands for national water security, the “three-type platform” is an inherent requirement and strategic fulcrum for developing new quality productive forces in water conservancy, achieving high-level self-reliance and strength in science and technology, and safeguarding flood control security, water supply security, food security, ecological security, and navigation security. Drawing on cutting-edge practices, this article proposes construction pathways such as strengthening whole-chain innovation, deepening the integration of “industry, academia, research, and application,” and innovating scientific research mechanisms. It aims to provide insights for scientific and technological innovation and high-quality development in China’s water conservancy, hydropower, and water transport sectors.