Abstract: In the water prevention and control work of coal mines，the development of thecollapse zone and water-conducting fracture zonecan seriously threaten the production safety of the coal mine and cause significant economic losses. To determine the development height of the overlying rock collapse zone and water-conducting fracture zone of the 3^# coal seam in the 30103 working face of Daliangwan Coal Mine，various methods such as on-site measurement (including leakage volume of flushing fluid，water level changes，television observation of boreholes，water pressure test，core geological recording and geo⁃ physical logging)，similar material simulation experiments and FLAC3D numerical simulation were adopted to comprehensively analyze the development height and evolution pattern of the collapse zone and water�conducting fracture zone. The results show that after the coal mining operation，the upper overlying rock will develop a higher water-conducting fracture zone，and multiple on-site measurement parameters will exhibit sudden change effects. The flushing fluid will suddenly leak，the water level will drop sharply，the permeability coefficient and permeability will increase，etc. Based on the sudden change characteristics， the development height of the water-conducting fracture zone is determined to be 109.4~161 m，and the development height of the collapse zone is 20.54~55.4 m. With the advancement of the coal mining face，the water-conducting fracture zone will expand significantly. Through similar material simulation experi⁃ ments and numerical simulation，it was found that at the 280 m and 288 m excavation points，the water�conducting fracture zone will expand to 148 m and 145.2 m，respectively. Through the combined analysis of multiple methods，the development height of the water-conducting fracture zone of the 3^# coal seam in the 30103 working face of Daliangwan Coal Mine is determined to be 145.2~161 m (average value 150.2 m)， and the fracture-mining ratio is 25.03. The research results will provide an important reference for deter⁃ mining the development height of the "two zones" in future coal mine production.

Key words: water-conducting fracture zone, collapse zone, field measurement, similar material simu? lation