In 22 1 BC, after Qin Shihuang wiped out the six countries and unified the Central Plains, he set out to formulate the strategy of finding Xiongnu in the north and Baiyue in Nanping. After a series of preparations, in 2 18 BC, Qin Shihuang ordered generals Tu Youyou and Zhao Tuo to lead a 500,000-strong army and launched a war to conquer the Vietnamese in Lingnan. Qin Junbing was divided into five roads, passing through Yuechengling in the north of Guangxi, Jiuyi Mountain in the south of Hunan, Nankang and Yugan in Jiangxi, and marched into Yue State in Guangdong and Guangxi today. Among them, Qin Jun, which captured Panyu, was the fastest. They passed through Jiuben Fortress, went down the Beijiang River, went straight to the Pearl River Delta and occupied Panyu. However, the two armies that attacked the Vietnamese in Guangxi today, because some Qin Jun officers headed by Tu Youyou adopted the policy of discriminating against the Vietnamese and pursued tyranny, caused the Vietnamese to resist in an all-round way. Because Vietnamese are familiar with the terrain and good at climbing mountains and wading, they attack Qin Jun at night, which makes Qin Jun miserable. Once the Vietnamese won, Qin Jun's grain route was cut off and supplies were insufficient, and Tu Youyou, one of the commanders, was also killed. Due to lack of food, the Commander-in-Chief was killed, Qin Jun suffered hundreds of thousands of casualties, and the war fell into a confrontational stage, which lasted for three years. In order to reverse the shortage of troops and the difficult supply of grain and grass, in 2 17 BC, Qin Shihuang ordered Yu Shilu, a military supervisor, to dig a Lingqu connecting Hunan and Lishui in Xing 'an, Guangxi. As the total length of Lingqu is only 34 kilometers, the engineering quantity is not large, and Qin Jun was completed soon. Lingqu connects the Xiangjiang River and the Pearl River system, and Qin Jun's wages can be continuously transported to Lingnan, providing a reliable material guarantee for Qin Shihuang to complete the great cause of Lingnan reunification. In 2 14 BC, Qin Shihuang ordered Ren Tao and Zhao Tuo to attack Baiyue tribe again. Qin Jun was on a roll, and soon defeated the resistance of Xi 'ou people in Guangxi and Luoyue people in central and northern Vietnam, and the whole Lingnan area was incorporated into the territory of the Qin Dynasty. In order to maintain the stability of Lingnan, Qin Shihuang ordered the soldiers who marched into Lingnan to stay in the local "garrison". In addition, there are a large number of Central Plains immigrants to Lingnan area. The remaining soldiers and immigrants, except a few who married migrant women from the Central Plains, mostly married Yue Nv. They brought advanced culture, agriculture and handicraft technology to Lingnan area, and made great contributions to the development of Lingnan. The war at the southern foot of Qinling Mountains was an important part of Qin Shihuang's war to unify China. For the first time in history, Lingnan was formally incorporated into Chinese territory, making the Yue nationality a member of the Chinese nation. It has played an important role in promoting the integration of Han and Vietnamese nationalities and the social, political, economic and cultural development of Lingnan.