人類對陸上領土主權的爭奪，以第二次世界大戰的慘烈犧牲為代價而終告落幕。但和平尚未及實現，另一個戰場卻已在海上開打，且有愈演愈烈之趨勢。為重建戰後秩序、維護世界和平，聯合國乃相繼於五○～七○年代召開三屆海洋法會議，針對海域劃界問題進行廣泛研討，並於一九八二年通過、九四年公布實施《聯合國海洋法公約》，意圖以「海洋憲章」之架構，來達成前述之目標。惟就現時而論，顯然有待改進之處仍多；特別是「島嶼地位」所衍生的爭議，尤為當今亟待釐清的重點之一。是以本文首先藉由對島嶼制度立法沿革的回顧，試圖探討島嶼之法理定位及其演變。其次則援引當代實務見解，進一步檢視島嶼在海域劃界的功能。最後則以中、日海權爭議為例，論述島嶼在海域劃界中的問題與盲點，俾有利於將來修正相關法案時的意見參考。

There are 145coastal states in the world, but there are more than 380 places of districts with disputes on maritime boundary delimitation. No more than one third of the whole Ocean Zones can be easily marked by boundaries. The international disputes on maritime boundary delimitation may threaten world peace. In order to protect postwar order and maintain world peace, therefore, the United Nations had held three meetings of marine law from the 1950s to 1970s. In these meetings, the issues about marking boundaries of Sea were under broad discussion, but there are still many debates on maritime boundary delimitation. At first, this paper reviews the legal history of the regime of islands, and analyzes the legal status of islands and their disputes. Secondly, it quotes the practical opinions and examines the present conditions and problems of islands for maritime boundary delimitation. At last, under the introduction of legal theories and practice about the debates and nuance of islands in maritime boundary delimitation, this paper may make a contribution for legislation to this issue.