In 1755 AD, the two armies officially fought. Ili was quickly razed to the ground because of its proper use of troops. At that time, Ili general Amursana led all the soldiers to surrender to the court, and Liu Tongxun also successfully spent this period of his military career. But it didn't end there. Not long after, Amursana fled on the way to remonstrate, burning, killing and looting along the way, which aroused Qianlong's anger and ordered troops to be suppressed. The situation was very critical at that time, and most of the Qing army's frontline leaders were trapped and killed. I was lucky enough to live forever. I was afraid of enemies and ambushes, so I ordered a retreat and was unable to deal with the rebels in time. As the supervisor, Liu Tongxun also agreed with Yongchang's approach and hoped to withdraw his troops. Only then did Qianlong know that many of the generals in front of him were dead. He just thought they would give up without a fight. So after Liu Tongxun returned to the court, Qianlong cured his sin and ransacked his home. The Qing Dynasty lost several generals, and the remaining Yongchang was also injured in the war. He was afraid of war.

Liu Tongxun was just a scholar and had no ability to lead troops in war. It is understandable that he chose to retreat in order to reduce the losses caused by the rebellion. Qianlong stayed away from North Korea and believed that our generals were brave and good at fighting and had sufficient military supplies to destroy the enemy. Liu Tongxun, who was in the army, knew very well the disadvantages of the army. Insufficient generals and lack of morale would lead to the failure of the war, so he chose to retreat. Emperor Qianlong decided to severely punish Liu Tongxun and others. "Liu Tongxun wrote a letter of dismissal and came to Beijing to be punished. Ziyi was also dismissed from his post and handed over to the Ministry of Punishment. Yongchangzi was dismissed and worked in the military camp. Yongchang and Liu Tongxun were in Beijing and handed over to the Ministry of Punishment. All banner countries and places collected money and tried every means Find it out to compensate the army." Not only was Liu Tongxun dismissed from his post, but his son Liu Yong and his son in Beijing were also arrested and sent to the Ministry of Punishment Prison.

In the eleventh year of Qianlong's reign, Liu Tongxun served as the governor of grain transportation and began to be responsible for supervising the river. In the next twenty or thirty years, Liu Tongxun took charge of river dredging and water control work many times. During most of his time as an official, Liu Tongxun almost spent his time controlling floods. The most rare thing is that Liu Tongxun is not an official who only works but does not contribute. After his treatment, the various floods he managed and the various rivers he was responsible for dredging basically had no problems anymore. During the process of water control, Liu Tongxun also easily solved a large group of corrupt officials. For example, several times when Liu Tongxun visited flood-stricken areas, local officials would complain to him about the shortage of supplies and their inability to stop the floods. The most typical example is that after the Yellow River burst its banks in Fuxiang, Henan Province, local officials shouted loudly that there were too many unruly people here and they could not receive food and grass at all. The reason Liu Tongxun controls water well is that he solves the problem from the source. At the same time, it also benefited from his practical spirit of diligent exploration.