Abstract: The coalbed methane desorption characteristics of Coal seam 3 in Yangquan is tested in the laboratory.The coalbed methane desorption time is calculated by using diffusion differentiation equation of adsorbed gas in coal grains and coalbed methane desorption time of Coal seam 3 in Yangquan is determined with graphics method.The study provides important parameters for coalbed methane development and utilization of Coal seam 3.