Abstract: In order to optimize the stope structure parameters of stage chamber mining method in a calcite mine and ensure safe and efficient mining，theoretical analysis and numerical simulation methods are comprehensively used. Firstly，the stability of the stope roof is theoretically calculated based on the load transfer intersection line method，the Platts arch method and the thickness-span ratio method.At the same time，combined with the theoretical formula of pillar strength and the safety factor method，the overall sta‐ bility of the pillar in the designed mining depth is evaluated. The theoretical analysis results show that the original 14 m stope span is not enough to ensure the safety and stability of the roof and pillar system，and there is a mining risk. In order to ensure the safe mining of the ore body，the stope span should be opti‐ mized to 9 m. Furthermore，FLAC3D numerical simulation software is used to verify the theoretical analysis results. The simulation results are consistent with the theoretical prediction. It is confirmed that the struc‐ tural parameters under 9 m span can effectively maintain the stability of the stope，and the optimization of the design parameters of the original stage room method is realized，which provides a technical basis for the safe mining of this kind of mine.

Key words: stage chamber mining method, roof stability, numerical simulation