Abstract: Raymond Aron is an important intellectual in France in last century. In this article，we will try to give an overall view of his political philosophy in the frame of the political sociology. Generally speaking，he advocates a reasonable politics built on an equilibrium analysis of social structure，which considers the politics both as a progressive historical process and as an art of irreversible choice and a long-term plan. The politics，as it seems to him，is actually the outcome of judgments and choices flowing together of all participants of history，even if sometimes it appears to be the result of a plan beforehand. From this emphasis on the autonomy of man，his liberalism adjusts that of Hayek，who overemphasizes the economic factor，and assimilates critically the division between formal freedom and real freedom in the sense of Marx，and arrives at a conclusion in-between，namely，a kind of political liberalism. For us，what he has done shows not only the respect for human nature，but also the anticipation for a good civil society.

Key words: reasonable politics, formal freedom, real freedom, political liberalism