In response to the legitimation crisis of the nation state in the era of globalization, Habermas has constructed, after criticizing and analyzing the traditional national identity theory, his theory of collective identity from the perspective of post-national structure, by taking constitutional patriotism and the universal human rights theory as its normative basis, so as to provide a possible path to resolve the multicultural conflicts in modern society. His opinions, however, have triggered intense debates among the nationalism, the republicanism and even the post-nationalism. The Habermas camp has also made its own response to these doubts and challenges. Instead of destroying Habermas theory, these debates help people think about the nation state and its fate in the era of globalization from the perspective of contrastive study, and are conducive to the comprehensive understanding of Habermas theory.