In this paper, a surface deactivation study of Cu1.0-Zn0.5-Ti98.5 oxide nano composite (CZT-ONC) as catalyst for photo-reduction of CO2 in aqueous solution is reported. The photoreduction experiments were conducted through five experimental cycles. The results demonstrated that the activity of the CZT-ONC decreased by increasing the number of testing cycle. The causes for declining the activity of the CZT-ONC catalyst was studied by investigating the surface condition of the catalyst before and after used by mean X-ray photoelectron spectroscopy (XPS) and field emission-scanning electron spectroscopy (FE-SEM) techniques and the results are discussed. It was found that the surface conditions (chemical state of the elements and morphology) of the CZT- ONC catalyst have been critically altered. Change in surface condition pointed that the deactivation process on the surface of the CZT-ONC was occurred and it could be considered to be the reasons for declining of the activity.