Abstract: Traditional upward mining of coal seam groups requires the interlayer spacing to be at least 4–5 times the mining height of the lower coal seam. During upward mining in ultra-close-distance coal seams, the roof and floor of the upper coal seam are disturbed by the caving zone induced by lower coal seam mining. This results in loosened and fractured rock masses that are highly susceptible to secondary instability during upper coal seam mining, potentially triggering sudden roof collapse and abrupt floor subsidence. Therefore, upward mining in ultra-close-distance coal seams (upward mining within the caving zone) represents a core technical problem urgently to be solved in coal mining engineering. To reveal the overburden failure laws and develop corresponding strata stability control technologies for upward mining in ultra-close-distance coal seams, the 113_up01 working face of Guotun Coal Mine, Shandong Energy Group, was taken as the engineering background. The height of the caving zone after lower coal seam mining and the lateral "three-zone" distribution of overburden failure under different interlayer spacings were investigated using theoretical analysis, numerical simulation, and field measurement. On this basis, a strata control method based on grouting reinforcement was proposed for upward mining within the caving zone, and its engineering applicability was verified through field implementation. The results show that after mining of the lower coal seam, the overburden failure forms a lateral ‘three-zone’ distribution in the post-mining caving zone, namely a suspended roof zone, a fracture zone, and a compaction zone. According to numerical simulation and actual variation of interlayer spacing, the strike widths of the suspended roof zone and the fracture zone are 11.5 m and 46 m, respectively, and the dip widths of the suspended roof zone and the fracture zone are 9.5 m and 55 m, respectively. The caving zone height and caving-to-mining ratio were measured by the borehole water injection method. The measurement, combined with numerical simulation, yields a caving zone height of 8.3 m and a caving-to-mining ratio of 2.36 after lower coal seam mining. Based on the lateral ‘three-zone’ distribution and the caving zone height, a zoned grouting reinforcement scheme for the working face was proposed, which effectively ensured the successful implementation of upward mining within the caving zone and achieved favorable field performance. The research results can provide a reference for upward mining in ultra-close-distance coal seams under similar geological and mining conditions.