Aimed at the problems that the study is not enough on the shock wave damage assessment methods of the target in building and the selecting aiming point is difficult, this paper proposes a concept of the volume-damage probability assessment, sets up a simulation model and gives out a computational method of the volume damage probability through the research on the shock wave propagation in buildings, and based on the gridding method, also presents a discrete point method to compute the three-dimensional damage probability. Finally, the result shows that the model accords with the fact, the disperse-point method is effective, and high in precision. Thereby, the concept of the volume damage probability assessment will be of great value to us in our research shock wave damage work and the precision guide missile and selecting aiming point.