Habermas’ theory of civil society presupposes two key concepts：lifeworld and public sphere. Lifeworld is his “worldview”. Differently from real worlds such as the objective world，the social world，and the subjective world，the reproduction of lifeworld is the soil in which civil society is generated. The public sphere is a communication network formed through rational debate for the purpose of achieving a certain consensus in communication among people. The public sphere is not an entity. It is neither an institution nor an organization. It is neither a normal structure nor a system. A dynamic public sphere is the precondition for a functioning，modern civil society. Any understanding of Habermas’ civil society theory must depart from these discursive foundatious.