Countries should coexist peacefully. "Harmony is precious", "Harmony is different" and "Xianning of all nations" mean to advocate peaceful coexistence between countries, and everything is harmonious, which embodies lasting peace. People should coordinate the relations between countries, so that people can live in harmony, attach importance to harmony, and it is also a common saying to persuade people to do good. After Qin Shihuang unified China, he insisted on "harmony is the most important thing" and realized "Xianning is the world", which gradually became the principle for China to deal with political and diplomatic relations with neighboring countries and even distant countries. It is precisely because of China's adherence to this principle that China has been able to maintain friendly relations with neighboring countries and distant countries for a long time. This external environment is an important historical condition for China to become one of the main founders of oriental civilization.