In order to analyze the overburden fracture range of the first mining face in Sanjiaohe Coal Mine  under different mining thickness conditions, the 2D-Block discrete element numerical simulation software was used to study the failure and distribution of overburden normal and interlaminar fractures after mining with 4, 6, 8, 12, 14, 16 and 18 m mining thickness single working faces. The overburden normal cracks and interlaminar fractures were studied separately, and the distribution patterns of overburden fractures were comprehensively determined. According to the horizontal deformation values and characteristics of the overburden, the fractures were divided into: severe rupture zone, micro rupture zone and re-closed zone. When the thickness is different, the height of the fall zone and the fracturation zone increase with the increase of the thickness. When the thickness reaches 14 m, the height of the fall zone and the fracturation zone reach the maximum, and then with the increase of the thickness, the height of the fall zone and the fracturation zone no longer increases.