The name of Reinhold Niebuhr was referred over and over again in America after 9.11 affair, so that he as a public intellectual was reemphasized after his death. And the concern focuses on such problem: how would Niebuhr look on American processing anti-terrorist war if he were alive. It is obvious that this revival closely related to the reflection on our current affair, especially on American world responsibility and exertion of its power. On such problems, Niebuhr discussed them in his later works which was still a virgin soil in academic area. However, the images of Niebuhr seemed to be very different in contemporary American media, which gave us an exposure in our blind point of research on Niebuhr. We will find a new Niebuhr differed from our past image who is not only a excellently political theology but also a positively social activist, and occupied the vocation of "Father of Neo-conservative" in American political spectrum. At the same time, we also confront such a problem that how can Christian theology provide a powerful reflection on our public area.