The rock mass is a nonlinear and discontinuous medium. Considered from the modern engineering scale

there should be a much better understanding of its physico-mechanical properties. Comparing with it

numerical simulation is a much better tool to know it because its merits of less time

low cost

simple manipulation. The basic situation of discrete element method which applies more extensively and develops more maturely among the discontinuous medium numerical methods is introduced

the several typical problems are expounded in detail

the researching progress of discrete element method is introduced in detail

and its relevant applications are also introduced

then the summaries are generalized

several developmental directions for the future are discussed.