Abstract: To understand the variation characteristics of dynamic shear modulus G and damping ratio $\lambda$ with the increasing depth H of marine soils, a series of resonant column tests are performed on silty clay with various depths taken from the three borehole profiles in Bohai Bay. The test results are compared with the strain-compatible dynamic shear modulus G and damping ratio $\lambda$ of marine soils in different seas and terrestrial soils cited from the published literatures. A remarkable finding of this study is that, the Bohai Bay silty clay represents the strong nonlinear and hysteresis behavior with low shear modulus and high damping, the dynamic shear modulus G and damping ratio $\lambda$ increase or decrease regularly with the increasing depth H. The maximum dynamic shear modulus G_max of various marine soils increases regularly with the increasing depth H. The marine soils in different seas represent more nonlinearity, hysteresis and higher small-strain damping compared with those of the terrestrial soils at the same depth H, and the correlation between the dynamic shear modulus G and the depth H of marine soils is very significant, and the proposed prediction equations for the maximum dynamic shear modulus G_max and dynamic shear modulus G based on depth H are quite universal for marine soils.