The classical studies of the Qing scholars, especially the scholars of the Qian-Jia ( 乾 嘉 ) period, have always been interpreted as a revival of the Han classical studies ( 漢學 ). Dai-Zhen's theory of "qi" ( 氣, air, material force) also has been interpreted as highly similar to, or even being derived from, the "yuan-qi" ( 元氣 , origin air, origin material force) theory of the philosophers of Han dynasty. This paper focuses on the differences between the "qi" philosophy of Dai and that of the Han philosophers. Through clarifying the charac-teristics of Dai's "qi" philosophy, we can see more clearly how Dai replaced the metaphysical meaning of the "qi" idea with his thought of communitarianism. Three points are suggested to argue the differences between Dai and the Han philosophers. First of all, the Han philosophers emphasized the superstitious mechanism of the "yin" air and "yang" air, while Dai emphasized the physical and mental air within our body. Second, the Han philosophers admitted nobleness and inferior-ity within human society, while Dai believed the value of equality of mankind. Third, the Han philosophers focused more on the cosmologi-cal progress of the origin of the universe, while Dai derived the importance of ethnic relationship of society from his theory of the differentiation of mankind. In conclusion, Dai was not interested in the discussion of metaphysical issues. Instead, he put all his effort on reinterpreting the idea "qi" through defending the rights and desires that comes together with our physical life.