This paper proposes a method for 2-D (two-dimensional) inversion of obliquely incident earthquake ground motion in layered elastic half-space, in which, the exact stiffness of soil layer and half-space are used for the inversion of incident acceleration time history and incident angle from surface horizontal and vertical acceleration records. The method of inversion is verified by an example of incident SV waves. The paper also discusses the error in traditional 1-D inversion model, in which, the incident horizontal acceleration time history is inverted from the surface horizontal acceleration record. It is shown that, the error is due to ignoring wave mode conversion in the 1-D model, and the error increases with the incident angle.