Abstract: Taking the actual drilling of multi-branch horizontal grouting wells in coal seam floor limestone layer of the Zhaogu No. 1 mine area as the research object. The well structure is optimized to reduce annulus pressure loss and drilling tool holding pressure, the compound drilling speed is increased by approximately 15% to 25%, the directional drilling speed is increased by about 20% to 40%; the drilling tool assembly is optimized, the dual stabilization drilling tool assembly is adopted to reduce the deviation and azimuth drift of the composite drilling process, the average daily footage rate has increased by 41.67%; a five-blade double-row tooth PDC bits with damping brackets and composite gauge and anti-wear is selected, the average composite drilling speed is increased by about 50%, and the average directional drilling speed is increased by about 56.52%; based on the traditional water-based low-solid drilling fluid, the drilling fluid formula is changed to optimize the performance of the drilling fluid, so that the sliding drilling speed is increased to 12 times the original drilling speed.