Abstract: Under the technology decoupling between China and the US, overcoming the challenges posed by key core technologies being “neck stuck” has become a primary problem for Chinese mega-projects. Based on the innovation ecosystem theory, using a longitudinal single case analysis, this paper explores the mechanism of collaborative innovation among numerous participants in mega-projects by analyzing China’s high-speed railway technology “catch-up” process. The results illustrate that: the changes in core platform promote the evolution of the innovation ecosystem; the collaboration models and mechanisms of collaborative innovation among participants evolve at different stages of the innovation ecosystem’s development in mega-projects; collaboration among institutions, organizations, and knowledge interacts mutually, supporting and promoting the formation, evolution, and technological innovation efficiency of the innovation ecosystem. The study enriches the theoretical framework of innovation ecosystems based on Chinese practices, expands the scope of research on platform theory and collaborative innovation theory, and provides enlightenment for overcoming the “neck sticking” of critical core technologies in mega-projects in China.

Key words: innovation ecosystem, collaborative innovation, mega-projects, technological innovation, China’s high-speed railway