While　the　classical　discontinuous　deformation　analysis　(DDA)　is　applied　to　the　analysis　of　a　given　block　system,　one　must　preset　stiffness　parameters　for　artificial　springs　to　be　fixed　during　the　open-close　iteration.　To　a　great　degree,　success　or　failure　in　applying　DDA　to　a　practical　problem　is　dependent　on　the　spring　stiffness　parameters,　which　is　believed　to　be　the　biggest　obstacle　to　more　extensive　applications　of　DDA.　In　order　to　evade　the　introduction　of　the　artificial　springs,　this　study　reformulates　DDA　as　a　mixed　linear　complementarity　problem　(MLCP)　in　the　primal　form.　Then,　from　the　fact　that　the　block　displacement　vector　of　each　block　can　be　expressed　in　terms　of　the　contact　forces　acting　on　the　block,　the　condensed　form　of　MLCP　is　derived,　which　is　more　efficient　than　the　primal　form.　Some　typical　examples　including　those　designed　by　the　DDA　inventor　are　reanalyzed,　proving　that　the　procedure　is　feasible.