Abstract: The joint monitoring technique of well-ground microseism for monitoring the development height of water conduction fracture zone in working surface is put forward in this paper. Based on the joint monitoring results of microearthquakes up and down wells, the quantitative and spatial distribution characteristics of microseismic events in vertical direction are analyzed. The relationship between the distribution of microseismic events caused by mining in working face and the development height of water diversion fracture zone is studied. Based on the theoretical calculation results of empirical formula, the development height of water diversion fracture zone is compared and studied. The results show that: The joint monitoring technology of microearthquakes up and down the well has high positioning accuracy. The microseismic events are mainly concentrated at both ends of the working face in the plane position, the stress concentration on the side of return air roadway in working face is obviously higher than that on the side of transportation roadway. The microseismic events in the vertical direction are mainly concentrated in the range of 80m above the coal seam, the number of microseismic events decreased sharply after 80m above the roof. The theoretical calculation results are consistent with the microseismic monitoring results. The research results provide an effective method for monitoring the development height of water diversion fracture zone.