Abstract: in order to sowe the technical problems of the safety mining under the water boady and to effectively protect the ground water,underground water resources and the safetyof the reservoir am bsed on the previou study achievemens.the stetistic analys s,theoreical cadculaton and engineering analogy combined method were applied to the verfication on the safetyof the coal mining under Yuecheng Watereservoir in the expansion block of shenjiazhuang Mine from the two aspects of the coal mining safety under the water reservoirand imining afiected to therservoir dan. The studlyresutshowed that the max height of the caving zone and factured zone development was 2 mt,the saetly coa ila with of F37 Fault and F月38 Faut was 87.3 and 129.0 m individualythe water prevention c al rock) illars eting was rational and a sartety mining could be realized in the exparnsion block.The surace ground subsidence,incli ed deformationcurvature deformaton horizontal dspacement deformation and horizontal deformation caused by the mining would not sweep to the reservoir ams and would not infuence to the safety of the reservoir dams.