Based on prevention and control of limestone water disasters in Jiulong Mine, directional horizontal well technology （Drilling natural law or artificial bending deflection tool making drilling hole curve and drilling hole axis extending in line with design track）, long distance level branch hole was constructed in top of limestone aquifer to find water passageway and other geological abnormity, the limestone aquifer was controlled by net with grouting improvement, changing the aquifer to relative water-resistance seam. The practice showed the good effect of the engineering improvement.