Political polarization is the most prominent feature of American politics. In recent years, the economic inequality in the United States is becoming more and more serious, the income gap is becoming more and more obvious, the middle class continues to shrink, the class solidification has begun to take shape, and the“poverty trap”has emerged. The worsening trend of inequality provides a crucial economic and social root for the escalation and intensification of political polarization. The imbalance between the rich and the poor, class differentiation, social injustice and unequal opportunities caused by inequality not only lead to the rise of right-wing conservatism, the proliferation of populism, the rise of identity politics and the crisis of political trust, but also aggravate the trend of partisan conflicts, extreme elite positions, ideological polarization, mass culture conflicts and social class division. Due to the rising trend of inequality and no sign of weakening political polarization, and the interweaving and strengthening of inequality and political polarization, American politics will not be able to get rid of the development trend of political polarization in the short term.