Abstract: The Discourse Ethics of J.Jurgen Habermas is a modern ethical paradigm,extended from his theory of communicative action,whose study boundary is limited to moral application of practical rationality strictly,so it shows features of deontology,formalism,Cognitive psychology and universalism.Its important significance lies in not only reiterating rational value and criticizing moral skepticism and moral situationism,but also responds moral nihilism and relativism strongly,brought by post-modern thoughts.Of course,the Discourse Ethics is not perfect,because it has embodied stylized and idealized limitations.

Key words: communicative action, Discourse Ethics, universalism, skepticism