The Xiongnu military minister Shan Yu died, and his younger brother Zuogu Liwang Yizhi set himself up as Shan Yu, and sent troops to attack the military minister Shan Yu Prince Yu Dan. Yu was defeated by a single soldier and surrendered to Han, and Emperor Wu of the Han Dynasty named him the Marquis of She'an, and died in Han soon after.

After Yi Zhixian ascended the throne, he carried out more frequent raids on the border counties of the Western Han Dynasty.

The Xiongnu Right Xian King was extremely resentful of the Western Han Dynasty to recover Henan and build Shuofang City, and attacked Shuofang several times in an attempt to recapture Henan.

In order to ensure Shuo Fang and give the Xiongnu a further blow, Emperor Wu of the Han Dynasty decided to implement the second step of the strategic plan, sending more than 100,000 troops to attack the Xiongnu Youxian King entrenched in Monan. The Han army was divided into two routes, with the West Route Army as the main direction of attack, with Wei Qing directly commanding 30,000 cavalry, marching north out of Gaoque, and commanding the guerrilla general Su Jian, the strong crossbow general Li Fu, the cavalry general Gongsun He, and the light car general Li Cai to command tens of thousands of troops, out of Shuofang, and directly attack the royal court of the right Xianwang. The Eastern Route Army was led by the general Zhang Cigong, commanding tens of thousands of cavalry, out of the right Beiping, attacking the Xiongnu Zuoxian King, pinning down his troops, and responding to the attack of the Weiqing Army.

In Yuanchun, Wei Qing led a large army out of the fortress and quietly surrounded the royal court of King Youxian at night. King Youxian thought that the royal court was far away from the Han realm, and it was impossible for the Han army to rush here, so he did not take any precautions, and King Youxian was drunk that night. Wei Qing took the opportunity to command the Han army to launch a sudden attack, the Xiongnu immediately made a mess, and the right Xian King woke up from his dream, frightened, unable to organize resistance, and hurriedly took his concubine and led hundreds of elite horsemen to break through and escape. Wei Qing urgently ordered the light cavalry captain Guo Cheng and others to lead the army to pursue north. Guo Cheng and the others chased for hundreds of miles, but when they couldn't catch up, they returned. In this battle, the Han army captured 15,000 men and women of the Youxian Wang's department, more than 10 people of the king of Pi, and hundreds of thousands of livestock, and won a complete victory. The Eastern Route Army led by Li Xi and Zhang Cigong also won the victory.

When the Han army triumphantly returned to the border fortress, the envoy sent by Emperor Wu of the Han Dynasty rushed to the army with the general's seal letter in hand, worshiped Wei Qing as the general, and added 8,700 households to the food estate, and all the generals were under the command of Wei Qing. The rest of the generals were also greatly rewarded. In order to reward Wei Qing, Emperor Wu of the Han Dynasty even named Wei Qing's three infant sons as marquis, respectively named Yichun Marquis, Ming'an Marquis, and Fagan Marquis. Wei Qing refused, but Emperor Wu of the Han Dynasty resolutely did not allow it.

In order to annihilate the Xiongnu and consolidate the border defense, Emperor Wu of the Han Dynasty ordered the general Wei Qing to send troops from Dingxiang, Gongsun Ao to be the middle general, Gongsun He to be the left general, Zhao Xin to be the former general, Su Jian to be the right general, Li Guang to be the rear general, Li Fu to be the strong crossbow general, led 100,000 cavalry to send troops to the Xiongnu, and Wei Qing killed thousands of enemies and returned. More than a month later, the Wei Qing Department sent troops from Dingxiang to attack the Xiongnu, killing more than 10,000 enemies.

It is worth mentioning that Wei Qing's nephew, hussar captain Huo Quai, participated in the war against the Xiongnu for the first time at the age of 17. He led 800 cavalry, pursued hundreds of miles, captured more than 2,000 Xiongnu, killed Yizhi Xianshan in Daxing's father through Ruohou's birth, captured Shan in his uncle Luo Gu and Xiongnu Xiangguo, Danghu and other high-ranking officials, and returned with his whole body. Emperor Wu of the Han Dynasty crowned the whole army with his merits, was named the champion marquis, and gave 2,500 households of food.

On the other hand, Wei Qing combined the two armies of Zhao Xin and Su Jian, and marched separately from the army, but they met Yizhi Xianshan army alone, more than 3,000 Han cavalry and tens of thousands of Hun cavalry to fight, fierce battle for more than a day, the Han army was not supported, Su Jian led part of the elite cavalry to break through and flee back. Zhao Xin was originally a general of the Xiongnu, and after the surrender of the Han Dynasty, he was named the Marquis of Xi, he saw that the Xiongnu army was overwhelming, and he wavered, and led 800 remnants of the army to surrender to the Xiongnu. Wei Qing was unwilling to kill the general, so he sent someone to send Su Jian to Chang'an. Emperor Wu of the Han Dynasty pardoned Su Jian and demoted him to a concubine.

After Zhao Xin surrendered to the Xiongnu, he offered advice to Yizhi and moved the Xiongnu army to the north, inducing the Han army to go deeper, and then striking at it when it was extremely tired. Seeing that the Han army was getting stronger, Yi Zhi took this suggestion and ordered to evacuate the Monan area and move far to Mobei.

In the two battles of Dingxiang, the Han army changed the previous practice of temporarily organizing armies in the face of battle, and established the center, left, right, front, and rear armies, under the unified command of the great general Wei Qing, and directly controlled the strong crossbow army, thus improving the ability of the armies to coordinate operations. This is the most tightly organized army since Emperor Wu of the Han Dynasty used troops against the Xiongnu. However, in actual combat, due to poor communication and communication, the right side defense army could not be coordinated, resulting in its separate encounter with the Xiongnu Shan Yu army, and more than 3,000 cavalry were almost wiped out. Although the Han army destroyed a total of 19,000 enemy cavalry, it did not achieve the expected purpose of attacking and destroying Yizhi Xiandan. Emperor Wu of the Han Dynasty did not have many military achievements this time, and rewarded the commander Wei Qingqianjin without any further benefits.

The Xiongnu were unwilling to fail, and successively attacked and plundered Daijun, Yanmen, Dingxiang, and Shangjun.

30,000 Hun cavalry to attack Shangjun, Yingbu led 60,000 soldiers to fight, the first to meet the North American aborigines and the Sixth Army, the North American aborigines' wooden shield failed to block the bow and arrow of the Hun cavalry, a group of soldiers fell in the arrow, the chariot of the Sixth Army rushed into the cavalry with a mace, 20,000 people fought out, killed more than 3,000 Hun cavalry.