Abstract:The breakthrough of key core technology has become an important issue of wide concern in the society. Recognizing that the fundamental factor restricting the breakthrough of key core technology lies in the national innovation system (NIS), this paper studies the construction of NIS for key core technology breakthrough. First, it defines the concept, subject and two main forms of construction, including Basic Construction and Targeted Construction, and analyzes their respective characteristics. Secondly, it studies the basic logic of two different forms of construction and proposes that the construction logic of Basic Construction is the supporting demand for NIS put forward by each link in the process of emerging technology evolving into key core technology, while the basic logic of Targeted Construction is to find the functional gap of NIS and make up for it. Thirdly, it demonstrates that the construction of NIS should take the functional structure as the guide and the constituent elements as the basic object and summarizes the feasible paths of different construction forms. Finally, the paper analyzes the construction mechanisms of different construction forms and compares the similarities and differences between the benefit driven mechanism and the mission driven mechanism, as well as their suitable application scenarios.