In the process of China's rapid urbanization, the influx of large numbers of people into large cities has become an irreversible trend. As a result, mega-city, including Beijing, and Shanghai, have witnessed housing problems in rent years, such that sharing rented space has become a popular choice for young people. Shared space can not only establish a good neighborhood relationship, but also strengthen the sense of community identity and belonging. Examining domestic situations in metropolitan cities such as Beijing, Shanghai and Nanjing, this thesis first analyzes the existing housing rental model and then present a survey conducted to understand young people’s demand for shared space. On this basis, the criteria and basic methods for designing shared space in rental housing are proposed that can meet young people’s needs for various functional spaces with shared kitchen, shared living rooms, shared office spac and so on, all while providing a place for people to communicate and socialize.