In 265 AD, Sima Yan replaced the Cao Wei regime to establish the Jin Dynasty, that is, the Western Jin Dynasty in history. In 3 1 1 year, Liu Cong led the Xiongnu army to capture Luoyang, the capital of the Western Jin Dynasty, and captured Emperor Huaidi, while the Western Jin army established Li as emperor in Chang 'an, continuing the Western Jin regime. Five years later, in 3 16, Liu Yao led the Xiongnu army to attack Chang 'an, surrendered to the emperor, and the Western Jin Dynasty ended. In the second year, Si Marui proclaimed himself emperor in Jiankang, and continued to establish the Jin Dynasty, known as the Eastern Jin Dynasty in history.

The origin of the royal family in the Jin Dynasty was the Sima family in Hanoi, and it was an official for generations in the Cao Wei era. For example, Sima Lang, Sima Yi and Sima Fu are eight brothers, so they are called the "Eight". Among them, Sima Yi has political and military talents. In the later period of Cao Wei, he resisted the Northern Expedition of Shu Han and pacified Liaodong, becoming an important minister of Wei State. When Wei Mingdi died in 239, both Sima Yi and Cao Shuang lived on their inheritance, but Sima Yi was later trampled to death by Cao Shuang. In 249, the Gao Ping Ling incident happened, Sima Yi regained power, and Sima's dictatorship began. After Sima Yi's death, his sons Sima Shi and Si Mazhao gradually consolidated Sima Shi's power. During this period, the three wars against Sima's family (known as Shouchun Three Oppositions in history) were all put down. In 263 AD, Si Mazhao ordered Zhong Hui, Wargo and Zhuge Xu to attack Shu, and Jiang Wei, commander-in-chief of Shu Han, blocked the enemy at Jiange. Finally, Wargo attacked Fucheng and advanced into Chengdu. Finally, Liu Chan surrendered to the Western Jin Dynasty (15), and Shu Han perished, which was the famous battle of Wei destroying Shu. After Zhong Hui and Jiang Wei attempted to defect, they were immediately suppressed by Si Mazhao. Si Mazhao died soon, and his son Sima Yan finally usurped the throne in 265, and Cao Wei perished. Sima Yan established the Jin Dynasty for Emperor Wu of Jin Dynasty, with Luoyang as its capital, which was called the Western Jin Dynasty in history.

At that time, the situation of Sun Wu was chaotic, and Sun Hao, the emperor of Wu, was extravagant and did not repair internal affairs. In 270, Xianbei bald tree in Hexi rebelled, and it was not settled until 279. At this time, is preparing to attack wu. He sent yang hu to Xiangyang to confront Sun Wu's famous Lu Kang, and sent Wang Jun to build a ship in Yizhou. Lu Kang died in 274. The following year, Yang proposed to attack Wu, but Jia Chong objected and gave up. After years of preparation, in 279, Wang Jun and Du Yu wrote that it was time to attack Wu, but Jia Chong and Xun Yu opposed it on the grounds that the northwest was undecided. Finally, Sima Yan decided to attack Wu Dong in 65438+February, which was the so-called Jin-Wu War. Sima Yan took Jia Chong as the commander-in-chief, with Wang Junjun in the upper reaches, Du Yu in the middle reaches and Wang Hun in the lower reaches neck and neck. Finally, in 280, when Jianye approached, Sun Hao surrendered, Sun Wu perished and the whole country was unified. After the Western Jin Dynasty unified the world, the social economy had a great recovery and development. Mainly, Emperor Wu of Jin implemented some positive policies. At the beginning of the Western Jin Dynasty, the world was booming, and the people who suffered from war were very eager for a stable life. Emperor Wu of Jin complied with public opinion, vigorously developed agriculture, promulgated family rules, reduced corvees, and set up "regular warehouses". The period of Emperor Wu of Jin Dynasty was the best social and economic period in the Western Jin Dynasty.