In this work, at first simple spinel cobalt oxide nono powder was synthesized by a simple hydrothermal route combined with a heat treatment, in the next step the commercially available with Electrophoretic deposition of Co3O4 film on indium tin oxide is presented. Co3O4 is p type semiconductor and ITO, n type and Co3O4 on ITO creates a pn junction. The material was characterized by X-ray diffraction, UV–visible spectroscopy for energy band gap estimation and scanning electron microscopy to morphology investigation as well as size distribution and The BET specific surface area of the prepared sample. The optical transitions for single layer and device is investigated. Co3O4 on ITO nanostructured thin films shows the outstanding photocatalytic behavior that enhanced photo-catalytic oxidizing so that After 120 min of UV irradiation, degradation efficiency reaches to 91%.