This paper describes the results of studies of the physicochemical characteristics of cobalt catalysts and methods for modifying them with alumina. The elemental composition, the peculiarities of formation of the structural and phase composition of cobalt catalysts are studied. The influence of the carbonization process of cobalt catalysts at a temperature of 550 °С on the specific surface is determined. The increase in the specific surface in cobalt catalysts was studied to proceed uniformly, as the formation of large grains and accumulations of active components was not observed. According to the results of X-ray diffraction (XRD) analysis, the formation of aluminosilicate phases, cobalt oxide, and cobalt are detected. The surface of cobalt samples was investigated by scanning electron microscope (SEM). Electron microscopy revealed crystallites of cobalt particles with sizes of 300‒400 nm. It is shown that in the course of modification with alumina, in cobalt catalysts active centers are formed that enhance their catalytic properties during the reaction of hydrogenation of acetylene to ethylene. It is found that cobalt catalysts exhibit catalytic activity in the acetylene hydrogenation reaction. On cobalt catalysts at a temperature of 160 °C at a conversion of 82%, the yield of ethy lene is 64.1%.