At the beginning of the Northern Song Dynasty, there were many attempts to recover Youyun 16 state. At the beginning of his succession, Song Taizong made two northern expeditions, trying to recover the hidden cloud 16. 1 year Northern Expedition, Song Jun was defeated by Gaoliang River. Song Taizong fled to the south by himself in a donkey cart. In the Second Northern Expedition, three armies of Song Jun all failed, and General Yang Ye was killed. After two northern expeditions, he took a defensive position against Liao. After Song Zhenzong Zhao Heng succeeded to the throne. Liao constantly harassed the Central Plains. Led by Zhong Sheng, the queen and leader of Liao, the Liao army invaded Song Zhenzong and arrived in Dingzhou near Kaifeng. Personal expedition at the suggestion of Prime Minister Kou Zhun. Song and Liao signed an alliance called Yuan through negotiation. The two countries maintained peace for more than 100 years, until 1 125, when Song and Jin made an alliance at sea and agreed to attack Liao. Although the Covenant between Song and Liao was reached through compromise, it was of great benefit to the border people of the two countries, the promotion of national prosperity and the economic recovery of the Central Plains. At the same time, the two countries developed trade and lived in harmony, which was the rapid sinicization of Liao country. The border between the two countries also tends to be peaceful. According to the History of Song Dynasty, people in white clothes in both countries did not listen to the war. At the same time, the economic exchanges between the two countries have accelerated the cultural exchanges between the two countries. The Emperor of Liao once said that there is no difference between the cultural relics of our country and those of China, which shows that the Liao country has been sinicized at this time. The nuclear war in Song and Liao Dynasties shows that both war and peace in China's history will promote ethnic integration and help to form a unified multi-ethnic country. However, Chinese culture has a strong centripetal force and influence. When ethnic minorities enter the Central Plains and become a member of our unified multi-ethnic country, they will be assimilated by Chinese culture.