Through comparing of the difference among understand single story C3I facility and multi-story above ground building(below ground),a typical underground target is established.

The theory includes the structure earth-penetrating projectile analysis, underground target analysis, penetration analysis, damage analysis, damage evaluation of personnel target and non-personnel target.

In this thesis,the finite-difference time-domain method is used to calculate the scattering waves of underground targets,The wave forms are plotted in two and three dimensions,It is proved that the FDTD method is of great value,At last the simulant experiments are made to compare with the calcu lated results and the comparison is satisfactory.