Qijiehe River submerges into underground at the end of Dacaokou Gorge and forms Dacaokou underground river. The riverway is about 30-65m in width and 35-55m in height. The river is wide at some places and narrow at other place. Sometime the flow is gentle and sometimes it is torrential. The outlet is on the bank of Liuchonghe River with the length of 2150m. The water yield at outlet is apparently more than that at the inlet, obviously, there are other supply resources.