Abstract: The No. 5 coal seam in a coal mine is complex thick seam. In view of permeable risks and the floor heave phenomena in driving process of its haulage roadway, mine pressure change curves are drawn to judge the pressure change rule of roof and floor through the observation of water change and the situation of roof and floor pressure. By using the mine DC method of geophysical methods to make the advanced detection, water disaster degree and floor heave laws are analyzed with the water sample test results from watered points.