Abstract: Based on the seepage mechanism in seam,a mathematical model of the seam pressure distribution was established,the pressure distribution conditions of the seam during the gas drainage process were calculated and the pressure drop transmission law of the seam was revealed.The Matlab7.11 was applied to simulate the coal bed methane reservoir stratum pressure drop transmission conditions of a mining block in Jincheng Mining Area and analyze the factors affected to the pressur e drop speed,the pressure drop size and the pressure drop transmission distance. The study showed the seam permeability,porosity and compression coefficient as well as the water drainage time would have high influences to the pressure drop speed at each point in the seam.The pressure drop would be positively related to the water drainage value,ffective thickness of the seam,permeable rate of the seam,porosity,gas drainage time and water content of seam.The seam permeable rate,porosity an d gas drainage time would be positively related to the pressure drop transmission distance in seam.