The detachments of communist 2nd Column under the command of Wang Zhen crossed Meridian Ridge and approached the town of Heshui. The 359th Brigade of the communist 2nd Column was assigned to take the town while the Instructional Brigade and the Independent 4th Brigade of the communist 2nd Column were tasked to ambush the reinforcement. As the 1st Regiment of the Instructional Brigade reached the Wormwood Grass Shop (Hao Cao Pu, ) area of Luo Er Plateau (Luo Er Yuan, ) region 10 km from Heshui, the communist scouts ahead were ambushed by the local nationalist cavalry on patrol. In a brief but fierce battle, a communist scout was captured alive by the nationalist cavalry. The communists feared that their plan was to be compromised, and attempted to rescue the captured scout, but Luo Er Plateau was a place extremely difficult to take but very easy to defend due to its terrain, and the 1st Regiment of the Instructional Brigade of the communist 2nd Column was forced to abort their futile attempts and move to the planned destination. The attackers therefore lost the element of surprise. At 4:00 AM on May 28, 1947, the 717th Regiment of the 359th Brigade made contact with nationalist garrison of Heshui to the northwest of the town, and all nationalists outside the town soon retreated behind the city wall. The commander of the Heavy Weaponry Battalion of the Reorganized 8th Cavalry Brigade of the nationalist Reorganized 82nd Division, Ma Shengzhi (), radioed the headquarters of the nationalist Reorganized 82nd Division at the town of Western Peak, claiming that the battle had already been raged on. By the evening of May 28, 1947, Ma Shengzhi radioed for help again, claiming that large enemy force was approaching the town of Heshui.