Beijing as Chinese housing system reform vanguard，has initially formed a more comprehensive multi-level affordable housing system. Based on the policy evolution of the affordable housing system，this paper shows the basic situation and data of the supply of affordable housing in Beijing，and summarizes the characteristics of the development of affordable housing in Beijing from aspects of housing security policy logic，the idea of affordable housing supply and structural changes，as well as affordable housing planning and design. The paper believes that for a long time，Beijing’s affordable housing supplies were used as a tool to make the short-term control in real estate market，and have been greatly influenced by housing market fluctuations and commodity housing policy，which is neither decided by the actual demand of the low-income families，nor have a stable supply mechanism. The research Proposes the policy recommendations and reflection on how to embed the affordable housing system in a long-term real estate regulation and control mechanism，and how to change the arbitrary and unsustainable situation of the “camera choice”.