Abstract: By using numerical simulation the paper studied the environments and influencing factors of application of coal seam sounding technique in roadway floor, analyzed the response characteristics of fault in coal seam sounding curve. The results indicated that in case where coal was highly resistant, floor and roof less resistant, coal seam sounding had good resolution for fault, the higher the contrast of apparent resistivity of coal and roof/floor was, the higher the resolution for fault. Coal thickness and the angle between roadway and fault also have effects on resolution of the fault detection.