Abstract: Ground grouting technology is effective method to prevent and control coal mine water hazard, and grouting multi-branch horizontal well is the foundation of ground grouting technology. Combined the characteristics of geological conditions, drilling techniques and grouting techniques, the truck-mounted drilling rig, rare-earth permanent magnet direct drive mud pump, EMWD and solid control system were selected, which were suitable for grouting well. The key technologies such as drilling structure, trajectory control, casing construction were studied. A set of drilling equipment and key technologies for grouting multi-branches horizontal well was formed, it had great significance to prevent and control water hazard in coal mines.