CeO₂–TiO₂ catalysts with four different morphologies were successfully synthesized by a hydrothermal method and tested for selective catalytic reduction of NO_x with NH₃ (NH₃–SCR). For the four catalysts, CeO₂–TiO₂ nanocubes (CT–NC) and nanorods (CT–NR) preferentially exposed {1 0 0} and {1 1 0} facets, respectively; furthermore, nanosheets (CT–NS) and nanospheres (CT–NH) mainly exposed {1 1 1} facet. Interestingly, CT–NH catalyst showed the best NH₃–SCR performance and the NO_x conversion exceeded 97% at 325 °C. Through a series of characteristic methods manifested that the short–range ordered structure of Ce–O–Ti in CT–NH catalyst provided stronger surface acidic sites to promote the high–temperature activity. Moreover, the abundant Ce³⁺ species and appropriate reduction ability on {1 1 1} facet of CT–NH catalyst also caused outstanding deNO_x activity. Reaction mechanism study showed that the Langmuir–Hinshelwood (L–H) mechanism and Eley–Rideal (E–R) mechanism existed simultaneously on all catalysts in NH₃–SCR reaction. Meaningfully, two types of E–R mechanism were present on CT–NH catalyst, while L–H mechanism was dominant.