The　authors　studied　wave　transmission　across　an　unfilled　linearly　jointed　complex　rock　mass　(the　wave　impedances　on　the　two　sides　of　the　joint　are　different).　(Fan　et　al.,　2018)　1　This　paper　further　presents　an　investigation　of　stress　wave　transmission　across　a　natural　filled　jointed　complex　rock　mass,　which　behaves　nonlinearly.　In　this　study,　the　conventional　characteristic　method　is　modified.　The　expression　of　the　particle　velocity　of　a　stress　wave　propagating　through　a　complex　rock　mass　across　a　nonlinearly　deforming　joint　is　established.　The　particle　velocity　transmission　coefficient　and　energy　transmission　coefficient　are　obtained.　The　nonlinear　effects　of　the　frequency　and　amplitude　of　the　incident　wave,　initial　stiffness　of　the　joint　and　wave　impedance　ratio　of　the　complex　rock　mass　on　the　particle　velocity　transmission　and　energy　transmission　are　discussed.　The　results　show　that　the　particle　velocity　transmission　coefficient　and　energy　transmission　coefficient　are　closely　related　to　the　incident　wave,　initial　joint　stiffness　and　wave　impedance　ratio.　The　particle　velocity　transmission　coefficient　increases　with　increasing　nonlinear　coefficient　of　the　joint.　It　is　noted　that　for　the　＇soft-to-hard＇　rock　mass,　the　particle　velocity　transmission　coefficient　is　always　smaller　than　1.0,　while　for　the　＇hard-to-soft＇　rock　mass,　it　can　exceed　1.0.　However,　the　energy　transmission　coefficient　is　always　smaller　than　1.0　for　both　the　＇soft-to-hard＇　rock　mass　and　the　＇hard-to-soft＇　rock　mass.　©　2020