The increasing proportion of the older population and changes in the Chinese family structure make older Chinese people more vulnerable to social isolation than they previously were. This article illustrates the development of a mobile social application for older people in urban areas in China. The application facilitates the organization of leisure-time activities between older people with similar interests living in adjacent areas. Preliminary social requirements of older people were collected through user interviews, and the major functions and features for the application were determined from the results of the interviews. Usability considerations for user interface design for older people were collected from literature and were integrated in the prototype of the mobile application. Older people's acceptance of the application was assessed by demonstrating the prototype to and interviewing 100 older people living in Beijing. The results highlight the critical impact of perceived benefits or relevancy on older people's adoption of new technology. Implications for the mobile social application for older Chinese people are discussed.