Abstract：Dynamic analysis of structures is one of main issues of structural design，especially for structures of rock masses containing various discontinuities. Numerical analysis is an important method for the problem. Block element method(BEM) is an effective numerical method for the analysis of rock masses. BEM is employed to expand the dynamic analysis of structures. At first，the formulas of mass matrix and damping matrix for dynamic analysis of BEM are presented；then，the dynamic equilibrium equations of the block system subjected to the inertia forces，the damping forces，the dynamic loads and the elastic forces are formulated. Finally，two examples are studied with the method. Both of the results are very close to those calculated by other methods. BEM has advantages in pretreatment of large numbers of discontinuities contained in rock masses；so it is expected to be widely used in stability analysis of complicated rock masses under dynamic or seismic loadings.
