The sandstone is taken as samples, and the RLW-2000M triaxial testing machine is used as the main equipment to test the axial stress-strain, the axial deformation in this paper. The axial strain is selected as damage variables, the damage degree expression is derived, and the effect of each factor on damage degree is studied. Research results show that axial deformation increases with the passage of time, and the hysteresis curve change from sparse to dense under the action of the dynamic loading. The axial deformation increase with the increase of the dynamic loading amplitude, and it increase with the decreased of frequency. The damage degree of specimen tends to be stable after mutation and increases with the increase of the dynamic loading amplitude. The research results will provide the scientific basis for us to disclose the rule of damage evolution of sandstone under the action of dynamic loading.