Abstract: In order to study coal tectonic difference under different failure mode and it’s gas adsorption，it taking the No.3 coal seam of Wangzhuang coal mine of Qinshui coal field in Shanxi province as background，gas adsorption of four different failure mode coal sample were measurement，the pore structure characters of different failure coal sample were analyzed by low temperature liquid nitrogen adsorption，and fractal dimension of coal mass pore was calculated by formula FHH，the structure difference of coal sample under different deformation and failure were compared.The results showed that gas adsorption ability of different coal sample were significantly difference for different failure model, the Langmuir volume VL increased from 24.34cm³/g to 36.16cm³/g，the coal failure degree increasing was benefit for gas adsorption，pore structure significantly difference for different failure mode coal sample，the variation range of median aperture of coal sample was 13.54～28.37nm，and variation range of total specific surface area was 0.389～0.965m²/g，fractal dimension variation from 2.389 to 2.682，on the whole, with coal sample failure increasing，coal aperture decreasing，and specific surface area was increasing，pore structure was more and more complicated，and the adsorption ability of coal was more and more higher.