《山海經》中的海中「蓬萊山」，發展到秦漢時期，以海中的「三山」或「五山」的地貌形式，寓託著初民對不死仙境的企求與想望。日益增衍的蓬萊三神山神話，其中對海底大壑、海中巨靈、海上他界的書寫與想像，積澱著先民對於大海的宗教情懷、哲學思辨與宇宙思維，具有豐富的文化意涵。本文重新檢視傳世古籍，《山海經》、《列子》、《列仙傳》、《海內十洲記》、《拾遺記》等文獻中有關「蓬萊山」的零散記載，發現在這些片段、隨意、簡短的有限蓬萊文本中，其意象、情節如「渤海」、「大壑」、「歸墟」、「巨鼇負山」、「龍伯大人」等，皆與「大海」關係密切，蘊涵著初民對海洋的浪漫想像、地理觀察，以及宇宙現象的描述和解釋，實具有豐富的「海洋」(原水) 思維，神話語言書寫表面的「隨意性」，潛隱著先民的世界觀與宇宙思維。本文即採比較神話學的研究方法，從神話的母題分析入手，嘗試在學界已有定論的論題上，重新檢視和探討蓬萊神話的所真有的海洋思維及其在古代宇宙論上的意義。

The concept of “Peng Lai Mount” in Shan Hai Jin went to Qin and Han Dynasty, it appeared in the form of indicating that the ancestor’s view of the eternal world. Within the increasing mythological research of “Peng Lai Mount”, the imagination and depiction of ravine in the sea, spirit in the ocean, and other worlds in the ocean shows that ancestor’s religious emotion and philosophical thinking towards the ocean. All these contain plenty of cultural significance. By re-examining the articles about “Peng Lai Mount” in ancient books, we found that, within the fragmental and limited records, concepts and plots such as “Bo Sea”, “ravine”, “furnace”, “turtle bear mount” are all close related to the “ocean” concept. These articles are full of ancestor’s imagination and observation towards ocean, and depiction and explanation towards the universe. Due to its abundance about the thinking of “ocean” (original water), languages in mythology try to depict the arbitrariness, which actually has something related to ancestor’s views of world and thinking about the universe. This paper adapts the theory of comparative mythology, starts with the fundamental question, and tries to re-examine and discuss the concept of ocean and its meaning, basing on some existing conclusions in this academia.