Abstract: Coal mining under the reservoir should not only ensure the safety of underground production,but also ensure that the water body and dam body of the re servoir will not be damaged. It involves safe mining under water and hydraulic structures. This paper is to carry out the feasibility study of underground safety productio n while the reservoir water body and dam body are not damaged by mining. Based on the geological mining conditions and surface reservoir、dam conditions of BLS Co al mine,Based on the analysis of the lithology of the overlying strata of each coal seam,it is determined that the overlying strata are of medium hard-hard type,and accor ding to the calculation rules of overburden failure height in close distance coal seam mining,the overburden failure height is calculated. On this basis,the prediction of th e height of the waterproof safety coal pillar,the analysis of the influence of the water flling in the working face and the calculation of the mining influence of coal seams C2,C3,C4 and C7+8 is carried out. The results show that:①In the reservoir area,the coal seam is deeply buried,the minable coal seam is thin and medium thick,and the overburden damage is low. There are stable,thick and non-mining damaged water resisting strata between the reservoir,shallow water body and mining damage. At the same time,no large-scale faults or collapse columns and other structures are revealed around the reservoir area. The good water resisting strata makes the reservoir,sh allow water body and There is no hydraulic connection in the area affected by mining. Mining will not change the original geological conditions of the reservoir water sto rage,the occurrence state of the reservoir and shallow water body is basically not affected by the coal mining,and mining under the reservoir is feasible;②After coal se am C2 mining,the final static deformation of the dam body is compression deformation,with a value of-1.3 mm/m. Relative tensile deformation is more beneficial to the p rotection of the dam body. In the process of coal seam C2 mining,the maximum dynamic tensile deformation of the dam body may also be within 2.0 mm/m. Within the a llowable deformation range,the dam body will not be damaged basically; ③When mining other coal seams,the dam body shall be reserved to protect the coal pillars or 0 ther measures shall be taken to ensure the safe use of the dam body.