本文透過綠島位於黑潮主流流路上的海洋位置，來討論其早期的涉外關係。 　　首先，就綠島史前文化和南島語族民族誌口傳資料中有關Sanasai傳說圈的意涵來看， 因黑潮流路的關係，讓綠島成為「史前民族遷移過程的中途站」之一。 　　其次，十六、十七世紀時，日本與菲律賓的貿易往來，利用黑潮和秀節風的配合，取 道台灣東海岸航行，也使綠島早有接觸日本或來往商船的機會，成為當時商船等待風候、 補給飲料水和燃料的中途站之一，並成為船難發生後，船隻漂流登陸的可能地點。 　　最後，小琉球漁民遭遇颶風後，隨黑潮洋流漂流而發現綠島，在驅逐島上雅美族後陸 續入墾，使綠島成為台灣東部漢人最早墾殖的聚居地。

　　　　　This article discusses the external relations of the Green Island under the influence of its oceanic location in early period of the island's history. Evidences from pre-history and from oral history of some of the Austronesian tribes in Taiwan indicates that, because the island is located right on the main stream of the Kuroshio, the Green Island became one of the stopping point of the migratory route of the prehistory people. 　　Secondly, in the 16 and 17 centuries, trade routes along the eastern coast of Taiwan between Japan and the Philippines took advantage of the Kuroshio and the trade wind. In such cases, the Green Island became a stopping point for merchant fleets to wait out for the trade wind to re-supply their ships and to refuel. The Green Island also became a place to land in times of ship-wreckage. 　　Lastly, fishermen from Lambay(小琉球) made landing on the island when encountering typhoon and drifting on the Kuroshio. They migrated gradually to this island after expelling original inhabitants, the Tao, and became the first Chinese people that migrated to Eastern Taiwan.