In recent years, there has been growing attention on Bike Sharing in urban China. More than 200 Chinese cities have developed Bike Sharing, which shows a surging growth. The usage of sharing bikes has changed the travel habits of urban residents. In fact, it is not only a new trip mode, but also the future of sustainable transportation. The existing research focuses on site layout and its impact mechanism, public travel demand prediction, travel time and space characteristics analysis, and the establishment and optimization of the bike management. Using different sources of data of two districts in Nanjing, including real bicycle usage and social survey data, the paper aims to identify the characteristics of sharing bike usage and analyze its influencing factors. Preliminary analysis of urban residents shows that the density of community and metro station are the most important factors affecting bike sharing flows and usage. However, in addition to the density of public bicycle and subway transportation facilities, the usage of public bicycles by college students is also affected by the purpose of travel, the location of the campus, and the layout of planning and other factors. These findings provide some useful information for city planners and Sharing Bike administrators who are designing or optimizing the bicycle sharing system aiming at maximizing usage rate, and they are helpful for other cities with intentions of planning and developing the Sharing Bike.