According to Xi 'an government website, Xi 'an's affordable housing project needs to pay the city supporting fee. The reason is to meet the construction needs of the project, but also to promote the development of the city and improve the living conditions of residents. Urban supporting expenses are used for the construction, maintenance and management of urban infrastructure, including the construction and maintenance of roads, bridges, water supply, drainage, power supply, gas supply and heating. For affordable housing projects, the construction and maintenance of these infrastructures are very important, because it is directly related to the quality of life of residents and the sustainable development of cities.