The medical facility is one of the essential public service facilities. Its spatial accessibility is an important indicator to measure the convenience of access to medical services and a significant factor affecting urban development and the living standards of residents. With the constant process of urbanization, urban agglomerations are formed and developing rapidly. The high-tier healthcare facilities in an urban agglomeration no longer only serve a single city but multiple connected cities. How to characterize healthcare accessibility and supply-demand relationships between medical resources and residents in the context of the urban agglomeration is worthy of being studied but still not fully involved in existing researches. To fill this gap, based on the conventional enhanced two-step floating catchment area method (E2SFCA) and considering the regional development discrepancy and medical preference of residents in the urban agglomeration, this paper proposes a new hierarchical two-step floating catchment area method (H2SFCA) to analyze accessibility to medical facilities. The applicability of the newly proposed method is demonstrated with reference to the Changsha-Zhuzhou-Xiangtan urban agglomeration case. The research findings suggest that: 1) A new method to evaluate accessibility to high-level medical facilities in the urban agglomeration is needed; 2) Due to the ignorance of intensive competition between potential demands, the healthcare accessibility in the core city is overestimated; 3) Residents' medical preference has various impacts on healthcare accessibility in different regions.

医疗设施是重要的公共服务设施之一。其空间可达性是衡量就医便利程度的重要指标，也是影响城市发展和居民生活水平的重要因素。随着城市化进程的不断推进，城市群形成并迅速发展。城市群中的高端医疗机构不再只服务于一个城市，而是服务于多个相连的城市。如何在城市群背景下表征医疗资源与居民之间的医疗可及性和供需关系值得研究，但在现有研究中仍未充分涉及。为了填补这个空白，在传统增强型两步浮动集水区法（E2SFCA）的基础上，考虑城市群区域发展差异和居民的医疗偏好，提出一种新的分层两步浮动集水区法（H2SFCA）来分析可达性。到医疗设施。以长株潭城市群为例，论证了新方法的适用性。研究结果表明：1）需要一种评估城市群高水平医疗设施可达性的新方法；2）由于忽视潜在需求之间的激烈竞争，高估了核心城市的医疗可及性；3) 居民