Abstract: In order to analyze the correlation between compressibility and permeability of lignite bearing pore structure, the T₂ pattern evolution curve and permeability of lignite loading process were tested by uniaxial compression online NMR test method, and the relationship between compressibility coefficient and permeability of lignite pore structure under different stress levels was studied. According to the calculation of T₂ map, it is found that the proportion of small holes, medium holes and large pores in lignite is 50%～60%, 20%～30% and 5%～20%, respectively, of which small pores can be divided into adsorption pores, and mesopores and macropores can be divided into seepage pores. In the whole process of load failure of lignite, the pore changes of coal body are mainly concentrated in seepage pores, and although the adsorption pores account for more than 50%, their contribution to the macroscopic deformation of coal body can be almost ignored. The compressibility of the seepage hole is strong, and the change value of compressible coefficient reaches 0.07～0.23, while the change value of compressible coefficient of adsorption pores is only 0.01～0.02. The change trend of coal permeability is consistent with the change trend of the compressibility coefficient of seepage holes, and the correlation coefficients are greater than 0.893, and the linear correlation between the compressibility of coal skeleton and the compressibility of seepage holes proves that the change of coal permeability with stress mainly depends on the seepage pores.