This paper aims to explain how adjacent areas which around existing urban agglomeration integrate into established regional intergovernmental cooperation system. By introducing theories of institutional diffusion, this paper reveals and discusses the process and mechanism of institutional diffusion in the Yangtze River delta economic zone which expands from 16 cities to 26 cities in the past 11 years. Based on interlocal agreements, this paper constructs cooperation networks to reveal the process from preinstitutionalization, theorization, to widely diffusion, as well as the network structures and features in each stage. What’s more, this paper explains the main mechanism of institutional diffusion for the integration of adjacent areas into regional intergovernmental cooperation is the top-down institutional pressure, while There are also multiple institutional tensions that city governments are able to effectively resolve through three strategies: balancing, selecting, and dissolving when integrating into the regional intergovernmental cooperation system. By introducing institutional diffusion into regional intergovernmental cooperation, this paper also reveals multiple institutional tensions in the diffusion of regional cooperation, as well as the problem of formalization in the institutional diffusion.

本文旨在解释城市群周边相邻区不断加入既有区域一体化合作体系中的过程和机制。对此,本文引入制度扩散的视角,以长三角经济区为例,探索了地方政府区域合作的制度扩散过程和动力机制。具体来说,本文借助长三角城市政府官网2008—2019年经济领域相关的协议数据,揭示了长三角经济区从16个城市到26个城市的扩散过程,即由前制度化和准备阶段的离散式、有限融入,转向理论化阶段的聚焦式、整体融入,最后到全面扩散阶段的集群式、全面融入的制度扩散过程。以此为基础,本文进一步发现了相邻区融入区域一体化合作的制度扩散机制,即在中央省 城市的自上而下为主的制度压力机制下,还存在多重的次生环境和制度性张力,而城市政府在融入区域一体化合作体系时,能够通过平衡、选择和消解三种策略应对解决。制度扩散视角的引入,也启发我们更多关注区域合作扩散中的多重制度逻辑以及制度扩散背后的形式化问题。