本文試圖討論，將東台灣視為一個客體時，如何界定其邊界或空間範圍，以及，這些界定邊界的不同方式，可能意含的社會脈絡與社會意義為何。基本上，東台灣的存在，不是先驗的，有其一定的歷史脈絡，更可視為當代的社會建構。同時，邊界是一個強調差異的指涉，劃定東台灣的邊界，其實在同步呈現東台灣與他者的差異性。本文逐一討論界定東台灣邊界的相關議題，並認為是經由歷史經驗，國家區域治理的政治作用，以及地理想像三者所建構而成。最後，本文指出，東台灣實為一組社會關係／網絡，在一個地理空間上的著床，本身即為一動態過程，其邊界是漸變的，權宜的，以及多義的。

This paper tries to analyze how to define the boundary of eastern Taiwan as a research object. Moreover, this paper also to discuss the social contexts and social meanings behind the different definitions for the boundaries of eastern Taiwan. Basically, the area of eastern Taiwan is Kind of historical space, and to be Kind of contemporary social construction as well. In addition, boundary always means the difference between two sides, defining the boundary of eastern Taiwan eventurally means the difference between eastern Taiwan and others. This paper argues that the boundary of eastern Taiwan was defined by historical context, state government and geographical imagination, Acturally, it is transitional, expedient, and multi-meaningful.