Cerium-modified Cu-SSZ-13 catalysts were synthesized by an in situ hydrothermal method, and Ce was incorporated through ion exchange. The catalytic performance and N-2 selectivity over prepared catalysts were evaluated in the selective catalytic reduction (SCR) of NOx by NH3. The physicochemical properties of the samples were characterized using XRD, SEM, H-2-TPR, XPS, NMR, XAS, and N-2 adsorption. The results indicated that Cu-SSZ-13 modified by Ce showed better NOx removal efficiency and aging resistance. The optimized condition was ion exchanged for 2 h in a cerous nitrate solution. The introduction of Ce effectively restrained the conversion of an active Cu component (Cu2+ -> Cu+) during the hydrothermal aging. Ce3+ species strongly associated with molecular sieve carriers and only slight skeleton dealumination was observed on the sample exchanged for 2 h, thus resulting in the further stabilization of catalyst active centers, which consequently maintained the catalytic activity and antiaging ability.