Hydrogenation of carbon monoxide has been studied under 15 MPaon modified Co-Cu-Y catalysts. Molybdenium was very effective for promotingcatalytic activity, and the synergistic presence of Co, Cu and Mo was necessaryfor the good catalytic performance in the synthesis of higher alcohols C_(2+)OH.Under our experimental conditions, a yield of 175 g/kg cat/h of mixed alcohols(C_1-C_5) was obtained with a C_(2+)OH proportion of 45％ in weight. A stronginteraction between CuO, CoO_y and MoO_x in the modified catalyst was ob-served. The presence of MoO_x stabilized the Y_2O_3 structure of the catalyst duringthe syngas reaction under high pressure illustrated by the X-ray diffractiontests. Hydrogenation of carbon monoxide has been studied under 15 MPa of modified Co-Cu-Y catalysts. Molybdenium was very effective for promoting catalytic activity, and the synergistic presence of Co, Cu and Mo was necessary for the good catalytic performance in the synthesis of higher alcohols C - ( 2+) OH. Unital experimental conditions, a yield of 175 g / kg cat / h of mixed alcohols (C_1-C_5) was obtained with a C_ (2+) OH proportion of 45% CoO_y and MoO_x in the modified catalyst was ob-served. The presence of MoO_x stabilized the Y_2O_3 structure of the catalyst during the syngas reaction under high pressure illustrated by the X-ray diffraction.