In this paper, a series of catalysts about CeO2 active sites prepared using reduced TiO2 (TiR) as supports were firstly used for selective catalytic reduction (SCR) of NO by NH3. The catalytic performance evaluation results showed that the NO removal efficiency of CeO2/TiR (CeTiR) was much higher than that of CeO2/TiO2 (CeTi). Hence, the aim of this study was to investigate the promotion mechanism of catalytic performance of CeTiR catalysts. The catalysts were characterized by XRD, BET, Raman, XPS, NH3-TPD and H2-TPR. The results of characterization revealed that CeO2 had a strong interaction with oxygen vacancies of TiR supports. The strong interaction resulted in more Ce3+ formation and better redox properties for CeTiR catalysts. In addition, it was confirmed that the better redox properties of CeTiR could be considered as the major reason of its high SCR activity via L-H mechanism but not acid properties. We expected that this study could shed some lights on the development of SCR catalysts for improving the interaction between Ti support and active species for enhancing SCR reaction.