Abstract: Taking Dongfanghong as a case company, this paper discusses the process and mechanism of how to promote the research and develop (R&D) agility of complex products. The main findings of this study are as follows: The research process of complex products can be divided into three phases: requirement identification and preliminary demonstration, overall design and module development, system integration and product testing. At different stages, enterprises need to deal with appropriate types of uncertainty, such as variation, foreseeable uncertainty, unforeseeable uncertainty and chaos. At the same time, enterprises need to develop the appropriate organizational IT capabilities, such as outside-in IT capabilities, spanning IT capabilities, inside-out IT capabilities, while enterprises need to take the organizational control, such as informal control, a portfolio of informal control and formal control, formal control. The main objective of the enterprise complex product development at various stages shows the dynamic characteristics, namely more attention to innovation, both innovation and reliability, and more attention to reliability. This paper not only helps to improve enterprise agility theory, but also has important reference value for China's complex product enterprises to leverage IT to promote R & D agility.