Nowadays, utilizing of alternative materials instead of lead in the environmentally sensitive and nontoxic material research in radiation shielding has attracted a lot of attention. Within this study, pure samarium oxide and samarium oxide/graphene nanostructures were successfully synthesized consecutively by facile hydrothermal method. The various physical properties of these materials were investigated using the conventional methods of energy dispersive X-ray spectroscopy (EDX), UV–Visible spectrophotometry, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and field emission scanning electron microscopy (FESEM). XRD result verified cubic phase of Sm2O3; however, the addition of graphene modified slightly the main structure. The result of FESEM showed the connection between the graphene nanoplates and samarium oxide nanoroads. The verification of the elemental presence for the both samples was performed through EDX analysis. The main factors of gamma protection properties such as mass attenuation coefficients (MAC), mean free path (MFP), half value layer (HVL), tenth value layer (TVL) and linear attenuation coefficients (LAC) have been measured for Sm2O3/graphene sample. They were 0.59 cm2/g, 0.23 cm, 0.16 cm, 0.54 cm, and 4.2 cm 1, respectively. According to these factors, it can be concluded that utilizing of graphene/Sm2O3 as a gamma ray protector can be useful. In addition to the experimental examination, simulation with GEANT4 simulation code was also used for both samples to examine the shielding parameters. The experimental and simulation attenuation for Sm2O3/graphene was about 19.2 % and 18.6 %, respectively.