The State of Vietnam is the only country that has historical documents and legal evidences on establishing sovereignty and exercising sovereignty over the Hoang Sa and Truong Sa archipelagoes. The illegal occupation of the sovereignty over the Hoang Sa archipelago and some rocky islands in the Truong Sa archipelago by some countries in the region is a serious violation of the sovereignty of the State of Vietnam, a violation of the United Nations Charter, the law of the Socialist Republic of Vietnam. international law, international law of the sea. This study will contribute to clarifying and clarifying the process of establishing sovereignty of the State of Vietnam over the Hoang Sa and Truong Sa archipelagoes.