Abstract: To find out the distribition of karst runoff zone in 13-15 mining area of Xi′an coalmine, judge general direction of the runoff zone by analyzing geological and hydrogeological data; confirm the location and direction of the runoff zone by transient electromagnetic combining drilling data and connectivity experiment. Result shows that a karst runoff zone has been detected in 13-15 mining area using the technology, the runoff zone strikes SN and is consistent with the main fault direction in the mine, which manifestes as caverns and dissolved pores, karst water runoffs from north to south. The technology has certain reference significance in the exploration of karst runoff in other mines and prevention of mine water.