Abstract: To explore the rules of the expansion of blasting cracks in coal under different gas pressures, based on the research results that the mechanical properties of gas-containing coal are different from those of ordinary coal, the strength modification is carried out on the basis of the physical and mechanical parameters of ordinary coal to determine the mechanical parameters of gas-containing coal. LS-DYNA finite element software is used to simulate the expansion of coal blasting cracks under different gas pressures, and the propagation and attenuation law of stress field in ordinary and gas-containing coal are analyzed. The results show that the radius of coal crushing zone and fracture zone increases with the increase of gas pressure, and the distribution of fracture is denser. In the near area of blasting, the peak pressure of gas-containing coal unit decreases slightly with the increase of gas pressure; in the far area of blasting, the peak pressure of unit increases, and the attenuation rate of stress field in gas-containing coal is lower than that of ordinary coal, and the stress action time increases, which causes the coal to break.