Abstract: Zhengzhou Metro Line 1 is taken as a study case to explore the impact of urban rail transit on commercial agglomeration and spatial patterns of commercial functions, based on POI databases of commercial facilities from 2013 and 2020. Furthermore, the mechanism behind the agglomeration of commercial facilities guided by urban rail transit is discussed. The findings indicate that: (1) The commercial agglomeration scale surrounding the stations of Zhengzhou Metro Line 1 has significantly increased. There are remarkable disparities in agglomeration intensity among different subway stations. Not only the existing commercial centers have been strengthened, but new ones have also emerged in peripheral areas along Zhengzhou Metro Line 1. (2) There exists a significant spatial correlation between the agglomeration of commercial facilities at subway stations and urban functional space. The models of agglomeration for urban commercial functional space can be classified into four types: gateway-oriented, central-oriented, local-oriented, and community-oriented. (3) The principal driver of commercial agglomeration is the enhancement of public transport accessibility facilitated by rail transit, while other important factors include the historical foundation and environment surrounding subway stations as well as the agglomeration economic effect.