Driven by the “Belt and Road” initiative, megaprojects of China have entered a global era and faces greater complexity challenges. Based on complex system management perspective, firstly, the management characteristics, sources of complexity and complexity characteristics of global megaprojects are analyzed; Secondly, the global megaproject development led by China since the founding of China is comprehensively sorted out and the complex situation evolution analysis is carried out; on this basis, the theoretical, practical and dual-cycle development path of the global megaproject management theory based on complex system management are discussed; finally, it is proposed five core issues that need to be studied in the governance of global megaprojects from the perspective of the “Belt and Road”. This will help enrich the application of theoretical scenarios of complex system management, expand the theoretical system of Chinese megaproject management, and provides a reference for the practice of “Belt and Road”.