為充分了解WTO在坎昆會議下的角色，本文首先透過對現實主義、自由主義，及馬克斯主義等主要國際關係理論內涵的探討，從國際關係與國際政經大環境的角度，探討國際組織在複雜國際關係網絡中的角色。藉由此三種世界觀對國際組織的理解與詮釋，本文進一步發現，做為一政府間國際組織，WTO在坎昆會議下起碼扮演下例之角色：美國經濟霍權的工具、提供美加歐日等經濟強權解決問題及謀取利益的機制、各方反映國內政經目的之、提供一自由與不受霍權控制的觀念市場、提供國家間制度化的合作機制、資本主義擴張的途徑、為核心國家剝削邊陲國家的工具，及已開發國家與開發中或低度開發國家對抗的舞臺。是以，WTO做為國際組織，因應國際環境需要而產生，畢竟無法不受國際關係或國際政經環境的影響，而面對複雜的國際關係環境，現實主義、自由主義，與馬克斯主義，可說提供本文相對系統化的分析經大環境中的定位、影響與角色。

　　　　　In order to fully understand WTO's roles in the Cancun meeting, the paper first explores the roles of international organizations in the complex networks of international relations from theoretical perspectives of realism, liberalism, and Marxism. Through these three world views' understandings and interpretations on international organizations, the paper finds out that in the Cancun meeting the WTO, as an intergovernmental organization (IGO), at least played the following roles: as American hegemony's instrument, as a mechanism for economic powers to solve common problems and seek interests, as a place for members to reflect their domestic political-economic objectives, as a free idea market without hegemonic control, as an institutionalized mechanism for inter-state cooperation, as an approach for capitalism expansion, as an instrument for core countries to an instrument for core countries to exploit peripheral countries, and as a platform for confrontation between development and developing or less-developed states.As a result, the WTO, as an international organization born of the need from international environment, is indeed hard to avoid any influence form international relations and international political economy. In the face of complex environment of international relations, realism, liberalism, and Marxism therefore can be said to provide relatively systematic analyses and thoughts for us to understand WTO's roles and influences in the Cancun meeting more clearly and comprehensively.