Abstract: The water-inrush risk evaluation of seam floor is the basic work for the prevention and control of floor water damage. The rationality of the prevention and control measures is affected by the evaluation. The evaluation index of water abundance was introduced based on the water inrush coefficient by taking the coal No.6 in Jungar Mining Area as the study area. The evaluation zone was classified as relative safety zone, transition zone, danger zone, and subdivided into 1, 5, 3 sub-regions, and the evaluation process was developed. The results show that: the relative safety zone based on water inrush coefficient was upgraded to the transition zone in the northern of the study area, and the danger zone was reduced to the transition zone in the southwest of the study area, that improved the objectivity of the evaluation and liberated the coal resources covered by the water. The evaluation basic on double-index can guide the prevention and control of floor water damage more scientifically and effectively.