In the literature on the migrant phenomenon in China, homeownership, city integration, and sense of happiness have all been examined, yet the synergetic relationship among these three factors has not been fully discussed. This study uses the 2012 National Dynamic Monitoring Database of Migrants created by the National Health and Family Planning Commission of China to explore the cooperative relationship between migrants’ homeownership, city integration and the sense of happiness. Generally, renting houses reduces migrants’ sense of happiness. However, with migrants’ greater integration into the place to which they have migrated, the sense of happiness of migrants who live in rental houses is enhanced to a greater degree than those who live in their own houses. This phenomenon is clear among migrants who have moved from less developed regions to developed regions and among those who have moved relatively longer geographical distances. This study demonstrates a city integration mechanism through which homeownership influences migrants’ sense of happiness. We contribute to happiness economics research and propose a scientific basis for speeding up new urbanization as well as improving a housing system which encourages both house renting and purchasing in China.