In the current study, yttrium iron garnet thin films substituted with cerium with the general formula of CexY3-xFe5O12 and values of (x = 0, 0.1, 0.3, 0.5, 0.7) were prepared through sol–gel method using spin coating technique and heating treatment on quartz substrates. Prepared samples were studied to check physical characteristics. X-ray diffraction analysis (XRD), scanning electron microscope (SEM), atomic force microscope (AFM), and vibrating sample magnetometer (VSM) were applied to study the impact of impurities of Ce on the structural characteristics, surface morphology of films and magnetic properties, respectively. Faraday rotation values of samples were measured at a wavelength of 632 nm. The image of atomic force microscope (AFM) of prepared samples shows that the thin films have a continuous and smooth surface.