Rare earth element (La, Y, and Ce) modified MgAl-hydrotalcites of MgAlM were synthesized from coprecipitation and calcination, and further loaded with CoMo active species to give CoMo/MgAlM catalysts. X-ray powder diffraction, inductively coupled plasma, and N(2 )adsorption isotherms indicate that MgAlM possess large BET surface areas (58-91 m(2)/g), and rare earth elements were successfully introduced into samples. CO2-TPD (temperature-programmed desorption), NH3-TPD, H-2-TPR (temperature-programmed reduction), H2S-TPS (temperature-programmed sulfidation), and Raman spectra indicate the presence of unique interactions between rare earth elements and Mo active species, which strongly affect the reduction and sulfidation behaviors of these catalysts. High resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analysis suggest that the addition of rare earth elements decreases the slab length and stacking numbers of MoS(2)and promotes the sulfidation degree of Mo oxides. The above characteristics make CoMo/MgAlM act as highly active catalysts for the water gas shift reaction (WGSR). This work develops a facile and cost-effective method for rational design of efficient catalysts for WGSR in industrial processes.