當代國際關係理論之發展，隨著社會建構論的崛起，進入新的階段。研究者常常從國際關係理論之歷史演進順序角度切入，探討現實主義與理想主義以來，國際關係理論的大辯論。據此，社會建構論常被視為是國際關係理論近期發展中社會學觀點的輸入，與傳統（新）現實主義及新自由主義做一區隔。其中，新自由主義通常由國際建制所代表的制度研究化身呈現，國際關係論者因此常常認定新制度論與社會建構論是截然不同的，甚至從認識論與本體論的一致性來看，認為後者超越前者。這種分類或說法，從組織社會學新制度論角度來看，頗值得再三斟酌。 在本論文中，作者自組織理論觀點論述：國際關係社會建構論實際上與組織社會學取向的新制度論有相容性以及不少共通性。國際關係研究者在探討社會建構論與新制度論的理論與實際關連性時，應進一步釐清不同類型的新制度論。就實際關連性而言，本文並以兩岸在國際關係「一個中國」之作為略做說明。

In the wake of the emergence of Social Constructivism, the development of International Relations theory has entered into a new phase. Researchers often address the subject in terms of the historical evolution of theories with reference to the Great Debates since Classical Realism-vs.-Idealism. As such, Social Constructivism, often regarded as a recent import from sociological perspectives, is commonly differentiated from (Neo) Realism and Neoliberalism. Among them, Neoliberalism is often tantamount to “new institutionalism” in International Relations. Some analysts therefore concluded that Social Constructivism differs from New Institutionalism and even went further to maintain that the former transcends the latter in terms of the consistency of ontology and epistemology. From the perspective of New Institutionalism of Sociological and Organizational Analysis (SOA) branch, the common distinction between Social Constructivism and New Institutionalism in IR is problematic and deserves re-examination. In this paper, it is argued from the SOA new institutionalist perspective that there is close linkage between Social Constructivism in IR and SOA new institutionalism: both share certain commonalities and complement with each other. IR theorists may well clarify the types of new institutionalisms referred to when dealing with the relationships between new institutionalism and social constructivism. The linkage per se can also be demonstrated in the case of Beijing-Taipei diplomatic practices on “one China.”