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.