The　overall　dynamic　mechanical　behavior　of　a　double-scale　discontinuous　rock　mass　with　a　nonlinear　deformational　macrojoint　was　investigated.　A　method　of　combining　the　split　three　characteristic　lines　with　the　piecewise　linear　displacement　discontinuity　model　(DDM)　was　proposed.　The　method　was　applied　to　investigate　the　transmission　coefficient　of　P-wave　propagation　normally　through　a　double-scale　discontinuous　rock　mass　with　a　nonlinear　deformational　macrojoint.　The　results　were　verified　by　comparison　with　the　results　of　P-wave　propagation　normally　through　a　double-scale　discontinuous　rock　mass　with　a　linear　deformational　macrojoint.　The　results　showed　that　for　a　small　amplitude　stress　wave,　the　nonlinear　deformational　macrojoint　can　be　simplified　as　a　linear　deformational　form　to　study　the　stress　wave　propagation,　whereas　for　a　large　amplitude　stress　wave,　the　effects　of　the　nonlinear　deformational　behavior　of　the　macrojoint　must　be　considered.　The　difference　of　the　effects　of　nonlinear　and　linear　deformational　macrojoints　on　large　amplitude　stress　wave　propagation　can　be　overlooked　in　the　low-frequency　or　high-frequency　regions.　In　addition,　when　the　incident　stress　wave　amplitude　and　initial　macrojoint　stiffness　are　sufficiently　large,　the　effects　of　the　nonlinear　deformational　macrojoint　on　stress　wave　propagation　can　be　overlooked,　and　the　effects　of　microdefects　must　be　considered.　The　influence　degree　of　microdefects　on　the　stress　wave　propagation　increases　with　the　increase　of　incident　stress　wave　frequency.　©　2020,　Springer-Verlag　GmbH　Austria,　part　of　Springer　Nature.