【Abstract】 Within 30 years after the end of the Cold War,the people in  the U.S. has experienced a drastic swing from exciting “end of  history”to annoying “Republic of Fear．”America is undergoing a historic  transition, which greatly affects American political culture，moving it  from traditional consensus building to extremist confrontation. Such  changes are reflected in all three dimensions of political  culture, namely, political value，political institution and political  behaviour. Current wave of transition of American political culture  further amplifies the impacts of US institutional rigidity and social  fragmentation on the culture itself．Considering the fact that the U.S.  is facing a reversion of American development trajectory, there are huge  uncertainties both in the transition of American political culture and  in American domestic and foreign policies.

【Keywords】American politics, political culture, transition,consensus-building politics, polarization, Trump