Since the housing system reform in 1998, China’s commercial housing prices have risen rapidly, and far exceeded the affordability of commonality. In order to solve the housing problems of middle and low income families, China launched the construction of affordable housing, which has greatly improved people’s livelihood and social welfare. The impact of affordable housing supply on the real estate market is also related to the interests of social groups. How to understand the relationship between the two types of housing has become an important reference for building an internally coordinated and efficient housing supply system.Combined with China’s special housing security and land system, this study theoretically analyzes the possible impact of affordable housing supply on the commercial housing market by constructing the equilibrium model of supply and demand. Based on the panel data of 248 prefecture-level cities in China from 2007 to 2016, the FEM and IV models are used to test the theoretical hypothesis, and the mechanism and heterogeneity are further discussed.The results show that: In the statistical sense, we find that affordable housing crowds out commercial housing supply through the competitive allocation of land, but it cannot replace demand in the segmented housing market, which eventually raises housing prices. Furthermore, the crowding-out effect is more obvious in the regions with low land financial dependence. But the economic meaning of empirical results is weak, and the crowding-out effect and the impact of housing prices can be ignored. This means that the supply of affordable housing basically does not harm the welfare of other groups.In general, this study has strong policy implications. On the one hand, China should establish multi-agent supply channels. Collective construction land and idle land owned by enterprises can be used to build affordable housing to ensure the independence of the land supply mechanism. On the other hand, some cities can gradually relax the access restrictions on affordable housing according to the actual situation. They can provide talent housing for college graduates and professional and technical personnel, and provide affordable rental housing for urban “new citizens” and migrant workers, so as to effectively divert the demand for commercial housing and stabilize the price of commercial housing.