Abstract: Based on researching and analyzing the deformation evolution law of the underground mining overburden "two zone" and the actual mining situation of underground mine "L" shaped working face of the Shenhua Open-pit Mine in Wuhai, combined with the current survey data, using the comprehensive analysis method, theoretical calculations and numerical simulation, the results show that the range of caving zone and fractured zone has a positive linear correlation relationship with mining width, which shows a sleek "M" type hump-shaped; the influence height is gradually increasing with the advance of the mining, then the influence height reaches to the maximum values of 42 m and 160 m when the mining width achieves to the full extraction width of 40 m; as the result, the fractured zones are connected, which threatens to the safety of mine mining.