This paper discusses the stope parameters of the sublevel subsequent filling stage in Daye Iron Shizishan section. According to the similar material simulation technology, which is the main means, displacement monitoring and internal stress monitoring, several conclusions are summarized as bellow: When the parameter of the room and pillar is 18m, the underground mining is safe and steady. Impacts, which come from different regions’ mining, is different, and the greatest impact comes from the pillar’ mining. Stress monitoring shows that before roof fell down, there is a process of stress concentration. The stress in the roof is shear stress, and compressive stress in the pillar.