To recognize Tocqueville (1805-1859) as a sociologist of religion and analyze his classical work "Democracy in America", this article examine his major scholarly contributions on religion and politics, which include (1) Religious definition and purposes: (2) The public opinions are the main sources of the identity; (3) The positive effect of religion on the politics; (4) The separation from religion and politics and its influence on the religion; (5) The sources of the religious authority; (6) The relationship between religion, individualism and conformity.