After the peasant rebel Army Zhang Xianzhong was "recruited" by the Ming Court in April of the eleventh year of Ming Chongzhen (1638), on the surface "kneeling and worshiping with courtesy", he secretly collected military food, nourished his strength, and "arrogantly did not obey the law", and the Ming Court repeatedly "did not follow the conscription". In the spring of the twelfth year of Chongzhen (1639), there was a famine in Henan, the drought in northern Jiangbei became a plague of locusts, the people complained bitterly, and the things of resisting grain and donating occurred frequently, Zhang Xianzhong judged the situation and considered that the time was ripe, but in the summer of the twelfth year of Ming Chongzhen, he joined forces with Luo Rucai's department to revolt again. In early May, Gucheng was recaptured. Followed by the march to Shaanxi.
On May 13, Zhang Xianzhong, Luo Rucai, and other troops met at Fang County and captured Fang County. He killed the county commander Hao Jingchun, who resisted and did not surrender, as well as his son Mingluan, the chief bookkeeper Zhu Bangwen, the instructor Li Zongqiu, the general Yang Daoxuan, and several members of the Ming army. After suppressing a group of local tycoons and inferior gentry, the peasants raised their eyebrows and breathed a sigh of relief, and many peasants joined the rebel army after Zhang Xianzhong attacked and occupied Gucheng, and the Ming Court immediately sent the marshals Zuo Liangyu and Luo Dai to lead the army from Xiangyang to Fang County to pursue and kill. In order to eliminate the effective forces of the Ming army, Zhang Xianzhong and Luo Rucai led the rebel army to take the initiative to evacuate the county seat of Fang County on July 25, and set up an ambush at Luohou Mountain, eighty miles west of the county. When Zuo Liangyu and Luo Dai led their troops to Luoshan, the peasant army attacked from all sides and launched a fierce attack on the Ming army, the Ming army was surrounded on all sides, and could not retreat, Luo Dai was shot by random arrows on the spot, and Zuo Liangyu escaped alone.
In this campaign, more than 10,000 Ming troops were wiped out, the military flags, large seals, documents, and letters were lost, and more than 10 million pieces of military funds were abandoned, giving the Ming rulers a heavy blow. Zuo Liangyu was demoted to the third rank by the official, and he regarded the matter with guilt.