The supremacy of UNCLOS has been overly emphasized, which is actually biased. Therefore, it is necessary to discuss the relationship between UNCLOS and general international law and to clarify that these two actually play a joint role in addressing maritime disputes. The linear baseline system of the mid-ocean archipelagos of mainland states should be regarded as having formed customary international law. In addition, historic rights, as customary international laws with dual legal attributes, can function independently at the level of general international law. Finally, the principle of equity, one of the principles of continental shelf delimitation, plays a vital role in delimiting the continental shelf as international customary law. Thus, the role of general international law in international maritime disputes cannot be ignored.