「聯合國海洋法會議」係迄今為止，聯合國所召開時間最長且規模最大的一次國際立法會議，其所產出的《聯合國海洋法公約》更成為國際政治領域中跨國決策的典範。綜觀學界多以新現實主義的觀點解釋該《公約》的制定過程，故常易陷入大國權力的競爭關係，又多以政治妥協、黑箱作業或包裹交易的方式解釋決策的制定。本文認為，此類研究難以說明為何第一至三屆「聯合國海洋法會議」的許多決策，未能盡如大國之意；且傳統將國際關係設想為固定結構的靜態分析架構，也難以說明國際社會的結構變化、行為體在面對不同議題時的認同變化、國家集團對國家的制約關係、與來自國家內部的壓力等諸多變項；故作者改以社會學領域中的魯曼社會系統理論，對保存完整會議資料的「聯合國海洋法會議」進行討論，期能開闢不同的思路。
　　本研究首先對世界海洋政治及法律系統的萌生及溝通運作的過程，進行扼要的說明，接著針對「國際法編纂會議」及第一至三屆「聯合國海洋法會議」的相關會議資料進行爬梳，最後歸結出三個可操作的觀察指標：一、國家主張與當代既有文本。二、議事規則。三、提案區分。其中，用以窺探當代意義框架的國家主張與既有文本，兩者是處於一種相互建構的關係，即國家會藉著相互溝通與對文本的觀察，而調整自我的主張；而其調整後的主張又會對既有文本產生影響，使文本作出修正。再者，議事規則與提案區分也必須互相搭配，如何掌握較佳的議事規則，並依此規則提出最佳的提案區分，為進行跨國決策研究時所不可忽略的觀察指標。
　　透過相關文獻的爬梳，本研究應為學界中首度將魯曼社會系統理論運用於國際關係的實證研究，故在研究方法方面難以找到模傚的對象，僅能藉著作者對魯曼系統理論的理解，在不違背理論的核心概念下，提出可操作的研究分法。作者衷心期望能藉此不同於傳統國際關係理論的知識典範，對跨國會議的決策制定過程進行討論，以拓展跨領域研究的溝通對話。

The “United Nations Conference on the Law of the Sea” might be the biggest and longest international law codification conference so far. Its outcome, the United Nations Convention on the Law of the Sea, has also become a paradigm of the transnational decision-making. Many Scholars would rather choose the neo-realism theory to explain the decision-making process and believe “package deal” as a useful means to achieve collaborate decisions. This article argues those explanations may not be able to explain why those final acts sometimes against powerful states or big states groups. Furthermore, multiple actors’ phenomenon in present international politics, actor’s identity shifting by different issues, and restraining factors from states groups to states may also challenge the accountability of traditional international theories.
In order to remove those doubts, this article has introduced an interdisciplinary approach using Luhmann’s social system theory to explain the decision-making process of the “United Nations Conference on the Law of the Sea.” It mainly combs out from official documents of the “Conference of the Progressive Codification of International Law” through the “United Nations Conference on the Law of the Sea, I - III” for summing up three essential operable factors: 1. National claims and referential documents of the conference, 2. Rules of procedure, 3. Amounts of distinguished proposals. The author argues when the amounts of distinguished proposals could match the rules of procedure and the meaning reference of engaged proposals could also match the meaning frame caused by National claims and conference documents, especially the later one, would help the international conference to make its decision.