Abstract: To study the difference of pore characteristics between deformed and undeformed coal in Shanyang mine field, the research was carried out for samples of deformed and undeformed coal by mercury injection, low-temperature nitrogen adsorption and scanning electron microscopy experiments. The results showed that the porosity, pore volume and specific surface area of deformed coal enlarged compared with undeformed coal. The pore volume and specific surface area of big pores decreased, while these of medium pores, little pores and micropores increased. Tectonism made inertinite break in deformed coal, and produced breccia. The appearance of breccia was irregular with sharp corner and straight edge, and there was no or little displacement between the breccia. Pores of the breccia were mainly about 2 μm and belonged to macroporous pores with better connectivity, which was relatively beneficial to the exploration and development of coal bed methane.