After World War I, the Versailles-Washington system was formed. Reason: "World War I" changed the power balance of imperialist countries. In order to carve up the world again, the victorious imperialist countries held the Paris Peace Conference and the Washington Conference successively, and adjusted the relations between Europe, Africa, the Far East and the Pacific. However, there are irreconcilable contradictions in this system, which collapsed with the outbreak of World War II. The "Yalta System" was formed after World War II. Reason: After World War II, great changes have taken place in the international power balance. The capitalist powers in Europe have been severely weakened, and the economic and military power of the United States has expanded unprecedentedly, becoming the overlord of the capitalist world. The political and military power of the Soviet Union has increased, making it the only country that can compete with the United States. On the basis of the balance of power, the United States and the Soviet Union re-divided the world map and sphere of influence and formed the Yalta system. In the 1980s and 1990s, the bipolar pattern collapsed and the world pattern developed towards multipolarization. Reason: The Soviet Union and Eastern Europe changed dramatically, the bipolar pattern ended, and the United States became the only superpower in the world. With the rise of Western Europe and Japan, China's national strength has increased after the reform and opening up, and Russian strength still exists. The multipolarization of the world economic power structure leads to the multipolarization of the world political structure.