Abstract: To reveal the effect of freeze-thaw on the pore structure of coal, a freeze-thaw test was carried out on the coal sample using a freeze-thaw machine. The pore evolution of coal samples under different freeze-thaw cycles was analyzed by using acoustic velocimeter and nuclear magnetic resonance equipment. The result shows that freeze-thaw can damage the pore structure and promote the development of pore of coal sample, and reduce the wave velocity of coal samples. With increase of freeze-thaw cycles, the micropore and mesopore of coal sample continue to expand and communicate, resulting in a significant increase in the number of macropore, the connectivity of pores, total porosity, residual porosity effective porosity and permeability of coal samples has increased, indicating that freeze-thaw can improve the permeability of coal seam, which is conducive to the extraction of coalbed methane.