Abstract: There exists a difference between old and new in the sphere of institutionalism of law. The old institutionalism, in a sense of sociology, defined the law as institution as social order and organizations, while the new institutionalism which is based on the theory of the institutional fact is aimed to “present a socially realistic development of normativism” and has some commons within the ontology recommendations of institutional fact, methodology pluralism and the place of practical reason. However, there also exist some differences as following: a formal and finalistic theory of action vs informal speech acts, the logical theories of practical reasoning vs the theory of rationality of practical reason, the normative conception of institutions vs the conventional conception of institutions, the attitude of positivism vs the attitude of post-positivism. During the processes of more than one hundred year, legal institutionism, within the dimensions of academic ways, theoretical resources and direction of development, has have converged effectively the relationship of normativism and anti-normativism, improved the theoretical basis and content, and enhanced continuously the theoretical autonomy of itself. As a benefit reference, the current domestic studies regarding legal instititution should focus more on “the normative development of empirical research” than before.