Abstract: Tongren mercury mine is a fissure and filling water mine deposit with high level. The crush of faultage and sudden inflow of water will lead to mine flooding when the mine is under construction. To avoid flooding accidents, TSP202 hydrology and geology accident prediction system is utilized. Purdah and slip casting technology is applied to fix up some curtain grouting holes on the working plane after grasping the overall hydrology and geology conditions of the surrounding rock of roadway. Slip casting forms waterproof curtain surrounding the roadway, preventing the faultage from being crushed and flood events from happening during the construction period of mine.