Abstract: Acoding to the well tests of 10 evaluation wells of coalbed methane in 8 mining distrcts in china,some factors influencing the permeability measurement in coal seams are discussed,it is considered that the harm of drilling operation to the coal seam,the texture of coal matrix and the higher effective terrestrial stress are the main influence factors;while the metamorphic degree of coal is not the main factor influencing the permeability measurement in coal seam,although it controls the cleat development in coal.