National-level new area is a large-scale comprehensive urban functional district designated by the central government based on the relevant administrative divisions and functional zones. The purpose is to carry out state developmental and reform activities. As the core content of Chinese strategic space, governance rescaling is the crucial thing in the process of establishment and development of national-level new areas. This paper builds an analytical framework from the perspective of scale rescaling to examine the practice of governance rescaling in national-level new areas. It adopts panel data of 215 counties of 16 national-level new areas involved between 2009 and 2017 and the regression model to test the economic effects of different types of governance. This paper concluded that governance rescaling of national-level new areas is the process of the function of all-level administrative subjects in the functional orientation, spatial zoning, administrative system and power allocation through rigid or flexible means. In practice, there are significant governance scale differences in regional spatial organization, administrative subject composition and power distribution among various national-level new areas, which form diversified governance types. Among them, the types of governance such as "Municipal District+Co-operative Work" and "Municipal District+Management Committee" have better economic effects, which can help to settle the problems of fuzzy power boundary and diversity of governance subjects. Whereas, the types of governance, such as "Municipal County+Management Committee" and "Cross-land City+Management Committee", show lower economic effects. The more complex the administrative relationship in the national-level new area spatial division and management is, the less they contribute to local economic growth. When a national-level new area spatial division crosses the border of prefecture-level cities or includes counties, management faces additional challenges. For national-level new areas which cross prefecture-level cities or contain municipal counties, it is necessary to promote the "removing counties and districts" in due course to simplify the main body of governance or to unify the logic of local development through the "strong power intervention" of superior governments. The Chinese case is theoretically significant because it suggests that the various trajectories and effects of state rescaling in different regions are contingent upon local social, economic, and political conditions.