Abstract: The conception of freedom is the core of liberal theory. By an analysis of liberal theories, we may divide liberalism’ conceptions of freedom into three kinds: classic liberal, libertarian and equalitarian. Classic liberalism holds the conception of negative freedom, which of the freedom means without interference. We may call the conception of freedom as “the freedom without interference”. Libertarianism carries on some ideas of classic liberalism, but put forward a principle of “obligation without imposition” against the welfare state. Libertarianism sometimes is called the new liberalism. Whatever the conceptions of freedom embodied as “without interference” or “without imposition” has some important flaws, there for need to be revised. Equalitarian liberalism takes on the task of revising liberalism, which supplement liberalism with equalitarianism. However contemporary liberalism is to be revised and supplemented, it can’t change the nature of negative freedom, and can’t refrain from the limitation of the conceptions of freedom.