Taking rail transit station area in Beijing as the research unit and considering both passengers and public service facilities in rail-station area as representative factors for supply and demand respectively, the paper investigates the spatial distribution characteristics and accessibility of public service facilities with Gaussian two-step floating catchment area (Ga2SFCA) method, analyses the influence of built environment based on the Transit Oriented Development (TOD) model. The findings reveal that overall, the distribution of public service facilities along the rail transit stations in Beijing generally shows a favorable trend. However, there are significant variations in accessibility among different types of facilities. High accessibility of social welfare, education, commercial and entertainment facilities can foster similar developments in adjacent regions, whereas medical and health services as well as cultural and sports amenities tend to be more randomly distributed. By examining both supply-demand dynamics for public service facilities alongside their accessibility levels, it becomes possible to effectively evaluate how well a station area functions as a regional center serving surrounding areas while also providing insights for optimizing urban facility configurations. 

以北京城市轨道交通站域空间为研究单元, 基于以公共交通为导向的城市发展(TOD)模式, 采用高斯两步移动搜索法(Ga2SFCA), 将站点乘客与站域公共服务设施作为供需双方, 分析公共服务设施在站域的空间分布特征、可达性情况及其建成环境影响。结果表明, 北京市公共服务设施沿轨道交通站域的分布整体上呈现良好的趋势, 但不同类型设施的可达性差异明显; 社会福利、教育及商业娱乐设施的高可达性可带动区域同类设施的发展, 医疗卫生和文化体育设施则偏向随机分布。基于公共服务设施的供需和可达性, 能够有效地检验作为区域中心的轨道交通站域对周边地区的服务能力, 为城市公共设施的配置和优化提供参考。