This paper aims to reveal the functional linkage between Guangzhou and Foshan by analyzing the multi-place-information of subway passengers. In the investigation, the spatial information about the location stations and the household registration locations of the respondents is obtained, and its position offsets to respondents' basic behavior places for residence, work and leisure are analyzed. Then, the spatial interaction process of the functional activities of the respondents is deeply explored, and the spatial flow characteristics of residents' activities across the city during the Guangzhou-Foshan integration are discussed. The results show that the residents in Foshan are more dependent on the subway transfer stations and their spatial interaction for leisure is deeper than that for residence and work; and that the spatial effect of the Guangzhou-Foshan subway is imbalanced in the process of space restructure , for instance, Guangzhou is more attractive for subway passengers in terms of leisure while Foshan is more likely to be a residential city.