In the book International Law, Zhou Yusheng expounded his theory of public international law. First of all, he believes that international law, according to its meaning, means that it is a law between countries, specifically, it is a code of conduct for countries in their mutual relations. In essence, international law is a code of conduct which is formed in the process of international communication, recognized by all countries, shows the will of the ruling class in these countries and is legally binding on all countries in international relations. Now when international jurists expound the concept of international law, they also take this concept from Professor Zhou Yusheng.
When discussing the subject of international law, Professor Zhou Yusheng pointed out that in international legal relations, the state is the person who enjoys rights and assumes obligations, that is, the so-called international personality, so the state is the subject of international law. The basic feature of a country as a subject of international law lies in its sovereignty. National sovereignty is inherent in the country as the subject of international law, and it certainly exists, not given by international law. On the contrary, international law is formed and developed on the basis of the interaction of sovereign States. The basic rights of a country include self-protection, independence, equality and jurisdiction. He emphasized that rights and obligations are related. A country enjoys rights, but at the same time it has the obligation not to infringe upon the rights enjoyed by other countries. A country has violated this obligation. This theory has been recognized by the international law circle today, and it is helpful to look at the hegemonic behavior of the United States in the light of the plane collision incident between China and the United States.
Professor Zhou Yusheng systematically expounded the general theory of public international law in his book International Law, with a complete theoretical system and unique views. At the same time, he introduced a large number of examples of foreign countries dealing with foreign-related cases and some diplomatic and international law practices in New China, which is of high academic value.