Based on Floating Population Survey in Beijing in 2012 and other specific surveys on floating population，this paper studies the social integration of Beijing’s floating population from five aspects，including institution segregation，economic integration，behavioral adjustment，cultural acceptance and psychological feelings.The results show that the floating population in Beijing has a low degree of social integration.Further，we analyze the causes that affect the process and results of social integration for Beijing’s floating population and propose some policy suggestions to improve the conditions of this group’s social integration.