In this study, the iron oxide thin flims have been produced by chemical bath deposition (CBD) method as a function of pH onto amorphous glass substrates. The surface images of the flims were investigated with scanning electron microscope (SEM). The crystal structures, orientation of crystallization, crystallite sizes, and dislocation density i.e. structural properties of the thin flims were analyzed with X-ray diffraction (XRD). The optical band gap (E-g), optical transmission (T%), reflectivity (R%), absorption coeffcient (alpha), refraction index (n), extinction coeffcient (k) and dielectric constant (epsilon) of the thin flims were investigated depending on pH, deposition time, solution temperature, substrate temperature, thickness of the flims by UV-VIS spectrometer.