Previous studies on urban spatial expansion focused on two-dimensional planes, which ignored vertical growth. In recent years, the development of three-dimensional urban space around subway stations has become a hot issue in urban research. This paper chooses the surrounding urban space centered on the residential subway station - Shengxianhu Station as the research object. Based on the surface buildings in 2008, 2014, 2020 and POI data in 2020, and with the help of GIS and POI analysis, this paper explores the relationship between three-dimensional expansion and functional distribution around the station, and analyzes the driving force of expansion, in order to provide a new perspective for the study of urban issues.