According to the theoretical interpretation of treaty law, though "UNCLOS" did not make clear the status of historic rights, it did not deny the existence of historic rights, either. Historic rights, belonging to customary international law, are the application of general international law to exceptional circumstances. Intertemporal law is an important principle of international law for a country to obtain territorial sovereignty and an important basis for solving the territorial disputes, which acts as an effective legal support for China to maintain its sovereignty over the South China Sea. To resolve the South China Sea disputes and safeguard China's interests of the South China Sea, China needs to examine the nature and status of historic rights from a higher perspective of international law and international law of the sea and to seek support from find legal resolution mechanisms such as the principles of discovery, preemption, and estoppel.