Abstract: Carbon nanotubes (CNTs) supported Co and Co-Ru bimetallic catalysts were prepared by an impregnation method. The obtained catalysts were characterized by TEM, XRD, TPR and TG techniques in order to elucidate the dispersion of metal particles, the interaction between cobalt and ruthenium, and the reducibility of catalysts. It has been found that Ru is a promoter to enhance the reducibility of cobalt, and results in cobalt reduction at lower temperatures. The catalytic activities of the as-prepared catalysts were tested with the probe reaction of hydroformylation of 1-octene. The results show that in comparison with Co/CNTs catalysts, Co-Ru/CNTs catalysts exhibit better performance in terms of higher conversion of 1-octene and higher selectivity to C9-aldehyde. This may be due to the homogenous dispersion of small metal particles and synergic effect of Co and Ru metals in bimetallic catalysts, which can be further attributed to the promoting effect of Ru metal in the catalysts.