Abstract: Geological connection was found at Hongyehe Reservoir and a coal mine, it is necessary to explore their mutual influence and safety. Through various methods such as drilling, sonic testing, intra-hole television and pressure water testing, the development and permeability characteristics of overlying rock fissures at the edge of the mined-out area were identified. The reservoir leakage under the influence of mining and its influence on coal safety mining were studied. We concluded that there were long-term seepage conditions in the mined-out area, and the leakage caused by the mined-out area was 1 263.63 m3/d accounting for about 1.09% of the annual average runoff of the reservoir, which had a certain impact on operation of the reservoir. Reservoir leakage increased the risk of water inrush disasters during the process of coal mining. In view of the adverse effects of the goaf collapse on reservoir leakage and the safety of coal mining, it is recommended to carry out engineering treatment.