Abstract: The movement pattern of overburden rock mass and the distribution of the “upper three zones” under fully mechanized mining conditions are studied from the 21406 and 21101 working faces of Hulusu Coal Mine through theoretical calculations, numerical simulations, drilling, water injection, and borehole camera technology methods. The results show that the movement of the 21406 working face presents a distribution pattern of “large in the middle, small on both sides”, with its movement speed initially increasing and then decreasing, reaching a maximum value after 138 m of the borehole, within the range of 138-174 m, it is the core interval for the development and evolution of separation layer space, which begins to weaken and close at 322 m. The separation space is distributed in the area about 180 m above the coal seam. The water-conducting fracture zone of the 21101 working face gradually evolves from an “arch shape” to a “saddle-shape” as the distance advanced, reaching a maximum height of 61.6 m at 60 m advance of working face. The water injection test measured the height of the water-conducting fracture zone at 65.39 m, The splitting and mining ratio is 22.54 times. The aquifer in the separated space is developed above the coal seam at a depth of 260 m, indicating that the fracture zone is distant from the aquifer in the separation layer space. These research results provide a solid foundation for separate layer grouting and roof water drainage.