In the discussion on inequality among Western academic circles，Paul Krugman always insists on the ‘political decision theory’ and some traditional institutions and norms，such as return to strong trade unions and high progressive taxation. In his many articles published recently on the inequality of wealth and income in the United States，he analyzed such phenomena as the lower inter-generational mobility and oligarchy，and presents some important viewpoints that can help us recognize the polarization between the rich and the poor and social conflicts in contemporary Western societies.