This essay deals firstly with Talcott Parsons’ life career and his vast writings. It, then, discusses his early theory of social action, which deviated from the main stream of his contemporary American sociological tradition, namely individual liberalism, utilitarianism and social Darwinism. Encountering the political and economic crises of 1930s, Parsons elaborated a theory of social action which depicts society not just a struggle for economic gain or political power but involving with individuals sharing common social meanings, ideals, and goals. After the World War II, Parsons formulated a grand sociological theory of “Social Svstem”, the so0-called structural functional theory which aroused academic interest and debate throughout the 1950s and 1960s. However, his general social theory was severely attacked by the proponents of Anti-Vietnam War, student unrest, social conflict, ecological, gay and feminist movements of the late 1960s amd early 1970s. In his later years, Parsons took a view of the evolution of societies and envisoned modernization as creating an open, free, pluralistic social order. He looked upon the U.S. as the realization of a modern societal community, within which religious freedom, ethnic group affiliation, and class solidarity would not threaten social integration and national identity. In fact, his defense of Western civilization and his claim for a social liberalism based on the societal community revealed his moral and political vision. Thus, contrary to his assertion of scientific objectivity and value-neutrality, his social theory is shrouded by and embedded in his moral ideal. This is why Steven Seidman calls his functionalist sociology but a liberal advocacy. Using critical perspective, this treatise finally reevaluates Parsons’ contribution to the further development of contemporary social and sociological theory.