In this paper, we aimed to investigate the linear and nonlinear optical properties of reduced graphene oxide-based metal oxide nanocomposite in comparison with reduced graphene oxide (RGO) and the effect of the process of reducing the oxygen groups of graphene oxide on the change of the nonlinear absorption coefficient of the reduced graphene oxide- zinc oxide (RGO-ZnO) and reduced graphene oxide-zinc oxide-iron oxide (RGO-ZnO-Fe2O4) sample. For this purpose, RGO, RGO-ZnO, and RGO–ZnO-Fe2O4 were synthesized using Hummers and hydrothermal methods, respectively, and then were analyzed using Fourier transform infrared (FT-IR), Ultraviolet-visible absorption (UV-Vis), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) were characterized. The XRD and FTIR analysis successfully synthesized RGO-ZnO and RGO-ZnO-Fe2O4 nanocomposites. Also, FT-IR spectroscopy indicated that absorption bands at 3340 cm-1, 1630 cm-1, 1730 cm-1, and 480 cm-1 are related to O-H, C=C, C=O, and Zn-O stretching vibrations, subsequently. The direct energy gap of GO, RGO, RGO-ZnO, and RGO-ZnO-Fe2O4 from UV-Vis spectra was reported to be 3.36, 3.18, 3.25, and 2.7eV, respectively. In addition, the third-order nonlinear optical properties (the nonlinear absorption coefficient) of all samples were investigated using the Z-scan technique with Nd: YAG laser (532 nm, 70 mW), and it was observed that the third-order nonlinear optical properties were increased from 8.3×10-4cm/W for RGO to 5.6×10-3 cm/W for RGO-ZnO-Fe2O4. پرونده مقاله