A series of KxMo/gamma-Al2O3 catalysts (x = 1, 2, 4, 8), used for the catalytic synthesis of methanethiol from carbon disulfide and hydrogen, were prepared, and characterized by N-2 adsorption-desorption, XRD, in situ pyridine adsorption FT-IR and NH3/CO2-TPD techniques. Experimental results showed that all the KxMo/gamma-Al2O3 catalysts can undergo sulfurization process during the reaction, and the alkalinity of the catalysts was significantly enhanced with increasing in the molar ratio of K to Mo. In addition, the alkalinity of the catalysts was found to be conducive to the improvement of yield of methyl mercaptan, while the acidity of the catalysts significantly promoted the disproportionation of CH3SH-CH3SCH3 and the hydrogenation to CH4. The conversion of CS2 was found to be 100 % on all the catalysts in the evaluated temperature range from 533 to 653 K. The optimal yield of CH3SH was found to be 94.6 % over K4Mo/gamma-Al2O3 catalyst, when the reaction temperature was at 583 K. [GRAPHICS] .