Yuan Chonghuan, with the support of Sun Chengzong, was assigned the task of conducting a major strengthening of Ningyuan's defenses in anticipation of a Jurchen attack.

However, the defensive preparation was hindered when Sun Chengzong was replaced by a new commander due to Wei Zhongxian's purge of all Donglin movement (eastern forest) elements in the Ming court.

[6] In 1626 Nurhaci received news of the Ming retreat and decided to advance towards Ningyuan on the advice of a Chinese defector, Li Yongfang.

[1] Initially Nurhaci attempted to convince Ningyuan's defenders to simply surrender, and sent a letter boasting that he had an army of 200,000, but Yuan did not believe him, and retorted that he had perhaps 130,000.

[2] The Jin army arrived and set up camp around the city, but they had misjudged the range of Ming cannons, which opened fire on them, and they were forced to retreat.

[2] Jin forces assaulted the city from another side using reinforced siege carts while archers provided cover fire, hoping to draw out the defenders so that their "iron cavalry" could flank them.

Some managed to reach the walls, but the lines of saltpeter that the Ming had previously set up were ignited, creating a protective barrier of fire around the city.

[8] Seeing that the siege was not going well, Nurhaci detailed a contingent of Mongol cavalry led by Jurchen general Wunage (武讷格) to attack the island of Juehua, which served as the primary granary of Ningyuan.

[9] Yuan promoted his strategy of fortifying key cities to retake lost land and began constructing defenses for Jinzhou further north of Ningyuan.

While the failure to take Ningyuan temporarily halted the Jurchen advance, the Later Jin increased pressure in the Bohai Gulf and the kingdom of Joseon.