The institutionalization is critical for the effectiveness of social policies. The pilot project influenced by top-down political authority is an important factor in understanding the process of policy institutionalization. Based on the Neo-institutionalism theory on organizational analysis， we construct an analytical analysis framework of "Regulation-Imitation-Normalization". Taking the institutionalization process of China’s rental housing policy from 2016 to 2020 as an example， we explore the differentiated impact mechanism in policy institutionalization driven by the fiscal incentive-based pilot project and tool innovation-based pilot project. The study finds the fiscal incentive-based pilot project mainly promotes policy diffusion in time and space through regulatory mechanisms formed by implicit pressure and direct incentives, and local governments in this context often adopt pilot policies driven by institutional supply. In addition to the direct role of the regulatory mechanism, the tool innovation-based pilot project also increases the horizontal pressure perceived by local governments through the imitative mechanism, thus indirectly promotes the policy diffusion. Moreover, under the influence of normative mechanisms, the tool innovation-based pilot project shifts the driving force behind local government policy adoption from institutional supply to institutional demand. This research shows that pilot projects can influence the institutionalization process of social policies by promoting widespread diffusion of policies and stimulating the initiative of local governments, but different types of pilot projects have distinct degrees and mechanisms of influence on the institutionalization process. And the central government can flexibly select different types of pilot projects and adjust the intensity of incentives or mandates according to the evolving policy context. This flexibility is an important characteristic of China's policy pilot system.

制度化过程对于实现社会政策的有效性尤为关键。受到自上而下政治权威影响的试点项目是理解政策制度化过程的重要因素。论文借鉴组织分析的新制度主义理论建构起 “规制—模仿—规范”的整合性分析框架,以2016—2020年住房租赁政策的制度化过程为例,探究了财政激励型和工具创新型试点项目对政策制度化过程差异化的影响机制。研究发现,财政激励型试点项目主要通过隐形压力与直接激励形成的规制性机制推动政策的时空扩散,地方政府在此情境中采纳试点政策的行为多是由制度供给所驱动;而工具创新型试点项目除了规制性机制的直接作用外,还通过模仿性机制增加地方政府所感知到的横向压力进而间接地推动政策的扩散;且在规范性机制的作用下,工具创新型试点项目使得地方政府政策采纳的驱动力从制度供给转变为制度需求。研究表明,试点项目能够通过推动政策的广泛扩散和激发地方政府的能动性来影响社会政策的制度化进程,但不同类型的试点项目作用于制度化进程的程度和机制具有明显的差异。中央政府根据不断变化着的政策情境灵活选择不同类型的试点项目并调整激励或授权的强度,这种灵活性正是中国政策试点制度的重要特征。