Due to the depth of the river and the heavy obstacles set up by Yao De in the river, the Perak army took a lot of effort to dredge the waterway near Jintang City. When Huang Dagen arrived at the naval dock of Genting City with his army, two days had passed since Dunzhu entered the city, and the Mongolian army besieging the city had already retreated. Kudu led more than 1,000 cavalry to the direction of Chengdu, and the Mongol cavalry under his command was not damaged in this battle, but the Mongol Han army that dismounted and fought lost several hundred people. Jiagu Long Gu led his army to retreat to Jianzhou City downstream, and he had received an order from Liu Heima to hold Jianzhou City.

Although it was already dusk, Huang Dagen, who had always been cautious, still ordered the whole army to enter the city overnight. On the second day, when Yang Bangxian put forward a proposal to pursue the victory, Huang Dagen vetoed it without thinking, and his decision was also supported by Zeng Yong, the commander of the teaching brigade. Zeng Yong had been a captain in the Wang Dechen Department of the Mongolian Army in Lizhou for many years, and he knew that the Mongolian army was cunning and cunning, and often lured the opponent to pursue by deceitful defeat, and then used the advantage of mobility to drag down and fatigue the enemy, and then ambushed him. Although the ancient Jiagu Dragon who retreated to Jianzhou was also an infantryman, there were still more than 1,000 troops, and it was still difficult to solve it for a while under the trapping beasts. Once the fighter is seized by Kudu, he suddenly kills back the carbine, and fights back and forth with the ancient Jiagu Dragon, and the battle will take a sharp turn. The Teaching Brigade and the Special Brigade led by Huang Dagen were both lightly armed troops, and although they could resist the onslaught of cavalry head-on, they were bound to suffer heavy casualties.

According to the strategy of the military-government joint conference, the purpose of this campaign was to take the entire western Sichuan Plain, and the capture of Chengdu and Genting City was the top priority. As the formulator of the battle plan, Huang Dagen of course knew which was more important, so he immediately ordered the reinforcement of the city defense of Genting City, and sent one battalion each of the Teaching Brigade and the Special Brigade to seize the surrounding forts. "A lonely city is difficult to defend", when Yu Jue established the Eight Pillars of Sichuan, he also built peripheral fortress strongholds for each core mountain city, and Yunding Mountain City was no exception. When Yao Shi'an was defending Genting City, he built a lot of outer forts, forming a complete defense system. The Mongol army was strong in attack and weak in defense, and also heavy in attack and light on defense, and did not play the role of Genting City's defense system, so it allowed the Thunderbolt army to succeed in a sneak attack. When Jiagulong fled to Jianzhou in ancient times, he also took most of the new annexed troops from the fortresses around Genting City with them, and the remaining old and weak remnants either fled in panic under the offensive, or knelt on the ground to surrender, and the Thunderbolt army did not take much effort to recover all these fortresses.

In the battle of Genting City, the first battalion of the special brigade suffered extremely serious losses, with a total of 500 people in the battalion, and only 230 people still have combat effectiveness at the moment, most of which are still the 200 people led by Dunzhu. The 300 men led by Dong Hu were basically killed or wounded in this battle, of which more than 90 were killed in the battle, more than 160 were seriously wounded, only more than 40 were still fighting and more than 30 were killed or wounded even the 50 prisoners who were later replenished. After taking Genting City, Huang Dagen immediately ordered a transport ship to return to Guan Kou Village, on the one hand, to bring back the wounded, prisoners, and comrades who had died in battle, and on the other hand, to bring in urgently needed fortress guns, ammunition, food, medical supplies, military technicians, and production equipment.

According to Ouyang Xuan's plan, Genting City will become the most important fortress city of the Thunderbolt Army in western Sichuan, and together with Pengshan City and Jiading City, it will become the core of the defense against the Mongol army's invasion of western Sichuan. To achieve this goal, in addition to strengthening the defense system of Genting City and building a naval army to control the upper reaches of the Tuojiang River, an arsenal will also be built in Genting City. As long as there was sufficient food and firearms, only 500 troops were needed to make the Mongol army retreat. The summit of Genting City has a vast area, and at its peak, 8,000 troops were stationed, and there was no shortage of places to build an arsenal. More importantly, the water transportation of Genting City is quite convenient, not only from the direction of Guankou Village to obtain iron, coal, timber and other important materials, but also from the upstream Pengzhou, Hanzhou, Mianzhou to obtain raw materials and grain, most of the latter states are also the land of fat, but also the direction of the Perak army will send troops.

Just when Jiagu Dragon attacked Genting City in ancient times, Cao Ergou also led his army to approach the west gate of Chengdu. Although Kudu led the cavalry to Genting City, he did not dare to be careless, and still carefully let the Thunderbolt cavalry protect the infantry phalanx. Sun Tzu's Art of War: "Ten are to encircle it, and five are to attack it", although the infantry of the field division is superior to the infantry of Liu Heima's Mongolian and Han army, the number of people even plus the basic militia transporting baggage is not more than twice that of the Chengdu defenders. At present, there are about 5,000 Mongolian troops in Chengdu, and Liu Heima drove many people to the city wall, so the number of attacking and defending sides is about the same, if only from the number of regular troops, the Mongolian army is more than the number of field divisions.

The two infantry brigades of the field division were stationed at the west and north gates of Chengdu – the south gate was attacked by the Perak navy, and the cavalry brigade camp was between the infantry brigades for support. This formation plan was actually Ouyang Xuan's meaning, and he took the staff to join Cao Ergou after the Battle of Wenjiang. Ouyang Xuan's strategic goal at this stage was to seize Chengdu City to control the land of western Sichuan, and then gain more space for development, rather than fighting with the Mongolian army. In fact, if the Thunderbolts had divided some of their forces to block the eastern gates, then the three thousand infantry of the field division would have been divided among the three gates, and each gate would have only a thousand men. This kind of dispersion of troops is really risky, and it is easy to be broken by Liu Heima's concentration of superior forces. Moreover, there are more than 1,000 cavalry in the direction of Genting City, which may attack the Thunderbolt army besieging the city from behind at any time.

Of course, it is a good thing to be able to completely annihilate the Mongolian army in Chengdu, but Ouyang Xuan understands that the current Thunderbolt army does not have the strength to completely annihilate the Sichuan and Western Mongolian army, and even if it is completely annihilated, it will cost a huge amount. Moreover, the enemy's cavalry strength was superior, which could cover the slow retreat of the infantry, and the cavalry of the Perak army was still no match for the Mongolian army. Although the Mongol cavalry suffered heavy losses in the First Battle of Wenjiang, most of them were lost under artillery. Although there were only more than 1,000 cavalry in Kudu, most of which were transferred from infantry, they were still not comparable to the cavalry of the Thunderbolt Army. At the moment, the Thunderbolt cavalry was severely damaged, and although they were still able to protect the flanks of the infantry with casualties, they were unable to engage in a head-on battle with the Mongol cavalry. Moreover, it was impossible for Ouyang Xuan to let the precious cavalry suffer casualties in order to completely annihilate the Chengdu Mongol army, once the protection of the cavalry was lost, no matter how strong the infantry of the Thunderbolt Army was, they would fall into the dilemma of being "punished for standing".

After blocking the west and north gates, the field division began to clear the siege equipment and fortifications on the city walls with artillery, but did not allow the infantry to attack. In the direction of the south gate, the waterway has not yet been dredged, and according to Le Quanan, it is estimated that it will take another two days to pass the gunboats. Zan Wanshou and Le Quanan had already sent people to get in touch with the field division, and had received an order from Ouyang Xuan to minimize the casualties of the soldiers, and to wash the ground with artillery fire before attacking. While the Thunderbolt Army was in full swing to prepare, Liu Heima was not idle. The Mongolian army first drove many people to dig a lot of trenches inside and outside the city wall under artillery fire, and then forcibly demolished the timber of many people's houses to build anti-artillery bunkers. After suffering enough from artillery, the Mongolian army finally found that these two methods were the most effective in preventing artillery bombardment.