Based on potential problem of unclear geological condition in the process of mining Ⅴ2 coal seam of Xuandong Mine of Zhangjiakou in Jizhong Energy Group Corporation Ltd., SYT geophysical exploration technology was adopted to survey aquiclude thickness and water abundance of underlying limestone, and vertical deepening probe was applied to lithological characters of 89 boreholes under Ⅴ2 coal seam in shortest time. This method had advantages of convenient installation, short construction period, and also could guarantee safety mining.