Evaluation　of　dynamic　excitation　response　in　the　vicinity　of　the　pile　foundation　is　crucial　in　soil-pile　interaction.　In　this　paper,　a　new　simplified　analytical　model　is　introduced　to　formulate　the　dynamic　impedance　of　an　inhomogenous　visco-elastic　soil　layer　having　a　monopile　with　a　non-reflective　boundary　interface.　The　main　idea　of　rocking　(overturning)　instability　of　the　pile　in　a　inhomogenous　soil　layer　has　been　equated　for　the　dynamic　impedances　(stiffness　and　damping)　in　a　frequency　domain.　The　model　will　develop　a　more　understandable　formulation　to　consider　the　relationship　between　impedance　factors　with　different　soil　parameters　like　damping　ratio,　homogeneity　and　inhomogeneity　of　soil.　The　continuos　and　parabolic　variation　of　these　parameters　across　the　boundary　interface　shows　the　model＇s　influence　and　suitability　for　practical　use,　since　the　mass　of　the　inner　boundary　zone　with　a　non-reflective　interface　has　been　considered　here.　On　the　basis　of　these　variations,　a　series　of　predictions　for　the　dynamic　impedance,　compatibility　have　been　numerically　varified　using　DynaN-3　as　a　main　stream　numerical　platform.　The　numerical　verification　shows　that　the　proposed　analytical　model　has　the　potential　to　be　used　for　pile　design　approach　controlling　the　nonlinear　behavior　of　pile-soil　interface,　especially　predicting　rocking　impedance　under　dynamic　loads　in　a　viscoelastic　soil　medium.