The study shows Hayek's evolutionary approach to the justification of liberalism. Firstly, it distinguishes a significant change in the methodological paradigm between Hayek' earlier and later phases of social theories. Secondly, it demonstrates Hayek's social evolutionary theory which is mutually complementary to the theory of spontaneous order, and thereby clarifies some vital criticisms of his evolutionary theory and his evolutionary approach to the justification of liberalism. Thirdly, it argues that the Hayekian liberalism may be viewed as an attempt to promote the development of civilization by means of preserving the moral institutions of liberty, and to promote the spontaneous evolution of such institutions in accordance with the course of liberty by imposing on it a set of meta-doctrines that are essential to the moral tradition of liberty.