At the end of the Warring States period, Zhao and Qin fought, and Xiongnu took the opportunity to occupy Hetao and the area south of Hetao. After Qin Shihuang annexed the world, in order to solve the border problem. In 2 15 BC, Meng Tian led 30 troops to attack the Huns. Qin Jun is mainly an infantry, facing the lack of mobility of grassland cavalry. In this case, Meng Tian was ordered to let hundreds of thousands of people build the Great Wall, from Lintao in the west to Liaodong in the east. It also connected Yan, Zhao Great Wall and Qin Changcheng, and effectively curbed the Xiongnu by using the terrain and natural barrier fortress. Because of this, Meng Tian has been stationed in Shang Jun for more than ten years and sublimated the Huns. Jia Yi once described Meng Tian like this: "Hu people dare not go south and dare not release their horses;" The scholar dare not bow down. "From then on, Meng Tian won the trust of Qin Shihuang, and his younger brother Meng Yi also became an official. Two brothers, one is Wen, the other is Xianggong, and Meng Tian and Meng Yi assisted Qin Shihuang, so-called "faithfulness". Meng Yi has strict legal rules and never favors powerful people. Zhao deserved it, and Meng Yi sentenced him to death according to law. Qin Shidian thought that Zhao Gao did his best at ordinary times, so he pardoned Zhao Gao. Therefore, the Montessori brothers became a thorn in Zhao Gao's side.
In the winter of 2 10 BC, Qin Shihuang went on a patrol, and Monk and Qin Shihuang were together. Qin Shihuang fell ill on the way and sent Monk to worship the mountains and rivers to pray. Qin Shihuang died before Meng Yi came back. Zhao Gao was worried that Fu Su's succession to the throne would be bad for him, so he blocked the news of Qin Shihuang's death. Later, he forged a will with Prime Ministers Reese and Hu Hai and staged a coup. The senior emissary gave Fu Su and Meng Tian false wills. In the false will, Fu Su was accused of not making meritorious deeds, but holding a grudge against his father and executing Fu Su and Meng Tian on trumped-up charges. Qin Shihuang was very strict when he was in office, and Fu opposed burning books to bury Confucianism. In a fit of pique, Qin Shihuang demoted Fu Su to the border and kept the border with Meng Tian. Su Weizhong committed suicide, but Meng Tian didn't believe it. Give the emissary Meng Tian to the first mate and put him in Zhou Yang.
After learning of Fu's death, Hu Hai wanted to release Meng Tian. Because Mencius had offended Zhao Gao before, he wanted to get rid of these two brothers. Zhao Gao also made a cruel remark in front of Hu Hai: "Before the first emperor, I want to make you a prince. Before I made you Prince, I was stopped by Meng Yi many times. " Hu first imprisoned and killed Yi, and then sent someone to kill Montaigne. Before he died, Meng Tian said, "My family fought for Qin for three generations, and made numerous contributions. Now I have 300,000 troops. Even if I am imprisoned, there is nothing you can do. I have kept my promise all my life, loyal to my liver and courage. I dare not insult the teachings of my ancestors, nor dare I forget the grace of my ancestors. " After that, he committed suicide by taking poison.
The soldiers of the three armed forces were all filled with indignation when they heard of Meng's death. The soldiers buried Meng Tian in the Dali River to the west of Suide, facing the tomb of Fu Shu in the distance. After Meng Tian's death, Lieutenant General Wang Li became the supreme commander of Qin Jun. At this time, the civil strife in the Qin Dynasty was serious, the mountains and rivers were crumbling, and the anti-Qin army won successively. Chen Sheng led the troops to Xianyang, and Wang Li led the troops to rebel against Qin Jun in 200,000. The grain was cut off by Xiang Yu, and Wang Li was arrested. Xiang Yu was afraid that 200,000 Qin Jun would rebel and killed 200,000 Qin Jun. Because of the civil strife in Qin, the Huns took the opportunity to occupy the Hetao area. One hundred thousand Qin soldiers who stayed to resist were finally defeated by Xiongnu. From then on, Meng Tian's 300,000 Qin Jun was completely defeated, and the Qin Dynasty soon perished.