日治時期台灣人與日本人的通婚並非如同今日的國際婚姻關係，而是日本帝國國民之間的異民族通婚行為，是謂「內台共婚」。比起一般婚姻，「內台共婚」可說是一跨越多重「邊界」的結合。 所謂的「邊界」，除了意指地理空間中的境界，同樣也包括社會學意義上的文化、價值觀等方面的差異與隔閡；並且由於當時日本人與台灣人之間制度性地存在「支配者─被支配者」的殖民統治位階關係，使得矗立於「大日本帝國」與「殖民地台灣」之間的「邊界」更形巨大而難以跨越。然而，內台共婚者卻以個人之力跨越厚重的界限，並且將「邊界」兩端的差異、矛盾與衝突濃縮於一個家庭的日常生活之中。 本研究試圖回答以下三個問題：(一)、跨界流動如何可能？綜觀日治時期，乃是一內地與殖民地間「距離」縮短的過程。所謂「距離」，不僅意指地理空間上的差距，更包括內台人在「社會距離」與「心理距離」上的接近程度。藉由觀察各種「距離」變化的過程，探究使得跨界流動的日台人通婚由「不可能」至「可能」的社會背景因素。(二)、是「誰」跨界通婚？由共婚者個人背景之分析，進一步探討存在於「內台共婚」的特殊階級性格。此外，影響共婚者決定結婚的關鍵性因素也是一個有趣的議題，其中包括愛國情操、利益追求，以及嚮往愛情這三種理由。(三)、跨界之後：共婚生活之分析。共婚家庭不僅必須面對來自外部的障礙，例如體制上的不友善以及社會輿論壓力等，也必須克服許多經營家庭生活的艱難課題。此外，跨界的流動也為共婚者本身及其混血兒子女的自我認同與定位帶來許多衝擊。 「內台共婚」者跨越多重的社會位置，其認同也依照不同的社會時空、生活處境而有所轉變，本研究基於史料耙梳、文獻蒐集與經驗訪談等資料，試圖理解共婚者跨越邊界而結合的流動與其複雜的認同軌跡。 / During the Japanese colonial period, the marriage between Taiwanese and Japanese was called "Nai-Tai marriage." The "Nai-Tai marriage" could be seen as an integration that crossed the boundaries between Taiwan and Japan. This study attempts to answer the following three questions: (1) Was the "Nai-Tai marriage" possible? The "distance" meant that not only the the distance from Taiwan to Japan, but also including the "social distance" and "psychological distance" between Taiwanese and Japanese. By observing the ways of "distance" changed, this research try to explore the social background factors of the "Nai-Tai marriage". (2) "Who" did it? This research analyzed the personal backgrounds and the social class of the "Nai-Tai marriage." In addition, the key reason of people decided to "Nai-Tai marriage" is also an interesting question. (3) How about their family life? The families of the "Nai-Tai marriage" had to overcome a variety of problems. In addition, for the "Nai-Tai marriage" people and their mixed-blood children, the mobility of cross-boundary also brought many shocks to their self-identity, and made them feel unsure of themselves in social situations. The "Nai-Tai marriage" people crossed multiple social positions, their identity also changed with their different social space, living conditions and social class. This study explained the "Nai-Tai marriage" people how to live their lives, and how their complex identity had changed.