Abstract: Social integration is an important issue arising from the development of capitalist society since the Enlightenment. This issue has attracted great attention of western academic circles. Scholars analyze the above problems from different dimensions. On this basis, Habermas put forward an idea of Communicative action theory, trying to combine the normative factors and factual factors in the process of social integration by using the theory of Communicative behavior, so as to solve the "Hobbes problem" of the post "metaphysical society". He advocated replacing practical rationality with communicative rationality, making overall use of two ways of system integration and social integration, guiding and controlling social integration with legal norms with normative and factual elements, and realizing the internal consistency between social integration action and the construction of a democratic and rule of law country. This urges us to re-examine the rational basis and practical mechanism of social integration from the perspective of the unity of facts and norms. However, Habermas's social integration theory overemphasizes the power of culture such as language, and there are inevitably Utopian elements.