獨占事業非當然受競爭法之非難，於獨占事業濫用其市場地位時，法律始有加以規範之必要。唯如何認定係屬不法之濫用行為？傳統標準多仰賴不確定法律概念，例如「無正當理由」此類抽象主觀之標準，操作上極易引發爭議，亦未必能充分考量廠商行為對經濟層面之影響。 為避免依循標準之不明確與不一致，阻滯市場上其他競爭行為，本文試圖將經濟面觀點與法律所重視的公平正義相平衡，使競爭政策的解釋更為客觀與精確，異於傳統法釋義學的觀點，尚透過經濟分析面向探討獨占行為之規範方式。 於此，本文提出各種基於經濟觀點出發之濫用獨占地位判斷標準，說明該等標準之定義與適用上之優劣得失；再藉由歐美判決之比較，觀察外國法院如何於具體個案中判斷事業是否濫用獨占地位；最後就我國案例，以文中提及之各種判斷標準為簡要分析，展現不同經濟觀點下之各類考量因素。

The purpose of competition law is to protect competition, but not competitors, national laws and courts have yet to clearly define what constitutes an abuse of dominant position. Since in recent years the policies in the U.S. and Europe have shifted from form-based approaches to more economics-based approaches, this paper attempts to examine the merits of economics-based approaches. It first clarifies the objectives of competition policy toward unilateral conduct, and then examines the strengths and weakness of major tests, including the profit sacrifice test, the no economic sense test, the equally efficient firm test, the consumer welfare test, and the unique test advanced by Professor Elhauge. Finally, this paper applies the test to actual cases to see which outcomes they point toward. This paper concludes that economics-based approaches hold great potential and, in the long run, will provide more predictable guidance in the area of the abuse of dominance.