Abstract: According to a low success rate status of the seam gas pressure measurement caused by the floor confined water of the seam, with the establishment of the floor water coning model, a test method was provided in consideration of the seam borehole drilling and sealing rate δ influences, the time of the floor water to brea k the seam was obtained, thus the borehole sealing time could be controlled and the success rate of the seam gas pressure measurement could be improved. The stud y showed that accurate prediction of the time for the floor water to break the seam would be related to the borehole sealing time and would determine the successful or failure test. Under the certain condition of the borehole drilling depth, the time of the floor water to break the seam and the cubic of the sealed seam depth would be in a positive correlation relation. A different drilling and sealing rate would directly set up the confined water coning speed and the seam breaking time. Generally the sele ction scope would be 0.1