Abstract: Within the scope of Xinhe Coal Mine in Jining Coalfield, there exists a multi-level detachment system composed of the weak layer surface between the three ash and ten_lower ash of the Carboniferous Permian as the main detachment surface, as well as the weak strata between the three sand and three ash in the coal bearing strata as the secondary detachment surface, similar structures are commonly developed in various coalfields in southwestern Shandong. To solve the impact problem on coal seam mining brought by this detachment structure, the research integrates high-resolution 3D seismic exploration and rock mechanics numerical simulation to construct a multi-factor coupled geological model, combined with the Mohr-Coulomb criterion, a 3D coupling analysis method of "seismic-hole drilling-mechanics" is proposed, and a quantitative model for the detachment structure is established. Differentiated mining technologies are adopted for different detachment surface areas to achieve accurate prediction of coal seam thickness loss rate. The research results clear up the specific impact of detachment structure on coal seam, based on the actual measured data of the 3301 working face, the detachment structure led to a 26% reduction in the average thickness of the 3th coal seam (4.15-10.15 m→3.04-7.45 m), the safety risks during the mining process are effectively reduced and the mining efficiency and safety of coal resource are improved.