Abstract: Previous studies mostly focused on policy diffusion at the micro level, lacking systematic observation and discussion of policy processes that, at the macro level, are neither hierarchical promotion, nor absorptive radial diffusion, nor diffusion among neighboring regions. Based on an analytical framework of “external conditions–action arena–behavioral outcomes”, combining event history analysis and dynamic Qualitative Comparative Analysis (QCA) methods, utilizing panel data from 27 provinces across China between 2010 and 2023, the influencing factors and driving patterns of the diffusion of the “strong provincial capital” policy were deeply analyzed. The findings reveal that: (1) The behavioral motives of local governments in adopting a new policy are complex, influenced by multiple internal and external factors such as institutional structures and socio-economic characteristics. The diffusion of the “strong provincial capital” strategy is an interplay between the “pull” from pressures such as self-development and peer competition, and the “push” from central political normative pressures; (2) There are regional spatial differences in the adoption of the “strong provincial capital” strategy, with central and western regions more inclined to implement it to promote economic development; (3) The “strong provincial capital” strategy can be classified into modes such as “single strong provincial capital”, “strong provincial capital + provincial sub-center”, “strong provincial capital + dual cores”, and “strong provincial capital + dual provincial sub-centers”, with differing influencing factors across different policy diffusion modes; (4) Configuration analysis results show that combinations of six conditional factors can facilitate the policy diffusion of the “strong provincial capital” strategy, among which national strategic guidance and opening up to the outside world are important factors for most provinces in adopting this strategy.