Since Marcos took office as President of the Philippines in June this year, the trend of the South China Sea policy of the new government of the Philippines has attracted much attention. Objectively speaking, maintaining balance among major countries, especially between strengthening the Philippines US alliance and deepening Philippines China cooperation in various fields, is a realistic choice made by the Philippines from its own national interests. At present, the Marcos government has shown relative caution on the South China Sea issue. During the general debate of the 77th United Nations General Assembly not long ago, Marcos also said that the Philippines intended to restart negotiations with China on the joint development of oil and gas resources in the South China Sea. Over the past three months, Marcos has repeatedly stressed that the South China Sea issue is not the mainstream of Philippine China relations and should not restrict or hinder bilateral cooperation. Related disputes in the South China Sea are difficult to resolve in the short term. As a temporary functional arrangement based on international law, joint development remains the common direction of China and the Philippines to properly handle the South China Sea issue. Of course, it should also be noted that the Philippines, while expressing its willingness to restart the negotiations on the joint development of resources in the South China Sea, also mentioned that "it cannot violate the domestic laws of the Philippines", which involves the application of laws for joint development, and is also a "tough bone" for China and the Philippines to negotiate on joint development in the past. Although the issue of application of law is related to the exercise of sovereign rights and interests, which has certain political sensitivity, China and the Philippines can deal with the issue of application of law in a "technical" way and gradually remove the "obstacles" in negotiations and consultations on the basic premise of the memorandum of understanding that has been reached between China and the Philippines on "not affecting the sovereignty and maritime rights claims of both sides, and not affecting the positions of both sides on issues related to the law of the sea". Neither the United Nations Convention on the Law of the Sea nor any other customary international law has established a specific system and clear rules for the application of the law jointly developed. The Convention only stipulates that the parties to the dispute should make every effort to make practical temporary arrangements before the settlement of the maritime delimitation dispute, and during this period do not jeopardize or hinder the conclusion of the delimitation agreement. In fact, there are no uniform standards and fixed ways to jointly develop the applicable laws in international law and practice. Therefore, on the premise of not affecting the claims of the sovereign rights and interests of both sides, China and the Philippines still have room for consensus on the application of their respective domestic laws in the joint development area. Looking at international practice, the legal application of joint development can be handled technically in a certain way, such as setting up a joint management organization to formulate unified rules, implementing zoning management in the joint development zone, or making provisions according to different categories of oil and gas activities, taxes, customs and other matters. The countries concerned generally tend to apply their own laws in the joint development zones, and there are many cases that can be used for reference by China and the Philippines. In the "Joint Development Case between France and Spain", the two sides "separately exercise their sovereign rights" in the joint development zone, and apply their own laws to part of the waters under their control in the joint development zone; In the "Iceland Norway Joint Development Case on Jan Mayen Island", the two sides apply their respective national legislation, policies and regulations on controlling oil exploration and development activities, safety measures and environmental protection in the joint development zone; In the "Senegal Guinea Bissau Joint Development Project", the two countries are in the joint development zone