Abstract: Based on the equivalent linear numerical method in frequency domain and two-dimensional strain space theory, a two-dimensional equivalent linear method is developed, which can be used to calculate the nonlinear seismic response of free field in layered half-space due to oblique incidence. First, the transfer matrix for the elastic layered half-space under oblique wave incidence is established. Then, the method to obtain the equivalent shear strain under inclined waves is established, and the strain-dependent equivalent shear modulus and damp can be obtained. Next, computational iteration is implemented until the error is small enough to be accepted. Finally, the last computed shear modulus and damp are used to describe the characteristic of the layered half-space, and the seismic response of the half-space can be calculated. The nonlinear seismic analysis for one layered half-space under inclined wave (SH, SV and P) is performed, and the effect of the incident angle on the seismic response is discussed.