Abstract: This paper deals with the two damage forms: rock mass crushing and plastic changes in underground engineering. It is based on Mohr-Coulomb criterion. The radii of crushed circle under the action of shock wave is obtained. It applies Von Mises yielding criterion to calculate the rock plastic zone under stress wave. It uses the KUBELA 420 explosive as an example. For sandstone in Chongqing under blasting load, the radii of crushed circle is not more than 1.7 times of charging radius and plastic zone radius does not exceed 25.06 times of charging radius. The prediction is close to the numerical simulation results.