Strait for navigation is generally classified as a traditional international strait in international law, which is defined as “a contraction of the sea between two territories, connecting two seas otherwise separating at least in that particular place by the territory. However, after the adoption of the LOS Convention in 1982, the definition of international straits becomes narrower or divided. It seems that there are two definitions for the international straits: one is the strait used for international navigation, and the other is the remaining kind of straits. The LOS convention defines the “strait used for international navigation” as strait connecting one part of the high seas or an exclusive economic zone (EEZ) with another part of the high seas or an EEZ. There are two criteria: one geographical and one functional. But it doesn’t clearly figure out the certain width is one of the criteria. 1998, the Year of the Ocean declared by the United Nations, Taiwan promulgated its Laws on the territorial sea and on the exclusive economic zone/continental shelf in January, while the mainland enacted its Law on EEZ/continental shelf in June in addition to its 1992 Law on the Territorial Sea and the Contiguous Zone. Thus the basic maritime regimes both in the mainland and in Taiwan have been formulated in accordance with the 1982 LOS Convention. Under such circumstances, time is ripe to redefine the legal status o the Taiwan Strait.