The free-floating bike (FFB) program is embraced by the cities worldwide and has influenced the existing transit service, especially the metro system. However, the urban regional mobility of FFB under the mixed relationship with metro is still unclear. In this study, we address this issue based on the three-month weekday FFB trips data in Shenzhen. First, we quantify to what extent the FFB competes with, connects with and complements metro system, and identify the corresponding travel scenarios. Then, the scenario-oriented travel communities that can reflect the distinctive urban regional mobility are detected. From the result, four kinds of travel scenarios are recognized, where the difference of metro service coverage towards access and egress FFB trips is further discussed. Moreover, by analyzing the development of the travel communities, we reveal the spatial and temporal characteristics of urban regional mobility. The findings enhance the understanding about the travel behaviors of FFB-metro integrated system, and can improve the daily operation of the transportation system.