In recent years，far-right extremism has been on the rise in the United States，and gradually moved from the political fringe to the public center，changing the social and political ecology of the United States. The current far-right ideology is characterized by nativism，authoritarianism and populism with the main manifestation of white supremacy，anti-Government extremism and social ultra-conservatism. Although the far-right makes up only a small proportion of the population，its social harm and political influence cannot be underestimated. Changes in the economic structure，demographic structure and political ecology of the United States have played important roles in the rise of the far-right lately. Considering the social origin，development conditions and the current response of federal government，the far-right extremism is likely to continue to develop steadily in the future.