In order to observe the height of water-conducting fracture zone and the ratio of water-conducting fracture zone to mining thickness in ZF9012 working face of a mine, two methods of borehole drilling and borehole drilling were used to carry out measurement and research. The height of water-conducting fractured zone on public surface was observed, and the height of water-conducting fractured zone in overburden strata of ZF9012 working face was 161 m, which was 16.1 times the mining thickness. The height of water-conducting fractured zone was 128.5 m and 162.3 m measured by two boreholes in underground, and the height of water-conducting fractured zone was 162.3 m by comprehensive analysis, and the ratio of water-conducting height to mining thickness was 16.2. The height of water-conducting fracture zone obtained by the two observation methods was similar and the error was small. It could be concluded that the ratio of height to mining thickness of ZF9012 working face was not more than 16.2, and the height of water-conducting fracture zone was not more than 162 m.