Brief：The present research analyses the theoretical innovation and key points of institutional building in international law related to the Belt and Road Initiative. It suggests: 1) China has increased its right and say in rule-making in international law. 2) The regulations of international law with regard to the construction of the Belt and Road mainly embodies in different forms of international treaties as well as the general principles and different institutions in compliance with the law of international treaty. 3) The international rules in the Belt and Road primarily incarnate in the domain of international economic law. 4) The construction of the Belt and Road can only be achieved by relying on the international cooperation in different forms. 5) The future development of the Belt and Road should be emphasized on regional organization and international law.