This paper introduces the incorporation approach with synthetic aperture radar (SAR) and contrast source inversion (CSI) based non-linear inverse scattering (NIS) approach for quantitative permittivity imaging for buried object under multi-layered heterogeneous ground media. It is challenging issue to retrieve a complex permittivity from ground penetrating radar (GPR) data, since the NIS problem considerably suffers from inaccuracy due to severe ill-posed condition. To overcome this limitation, this paper introduces the SAR image based region of interest (ROI) limitation in the CSI optimization scheme, where the number of unknowns are massively reduced. Furthermore, the SAR image is also upgraded by the pre-CSI optimization, where the Green's function and background clutter for heterogeneous background (e.g., multi-layered medium) are accurately generated. The FDTD based numerical tests, assuming GPR observation model, show that our proposed scheme effectively reconstructs a dielectric property of buried object, even in severe condition.