The influence of manganese promotion on the catalytic performance of Rh/CNTs catalyst for ethanol production from syngas was investigated. With the addition of manganese, CO conversion and ethanol yield increased significantly. The effects of reaction temperature, pressure, and H-2/CO molar ratio on the manganese-promoted Rh/CNTs catalyst were studied. With pressure increase, alcohol selectivity increased, while methane selectivity decreased. The high H-2/CO molar ratio improved CO conversion and suppressed the formation of CO2. The catalysts were characterized by Brunauer-Emmett-Teller method, X-ray diffraction, transmission electron microscopy, temperature-programmed desorption experiment, and X-ray photoelectron spectroscopy to clarify their physical and chemical properties. It was found that the high activity of the Mn-Rh/CNTs catalyst and the corresponding high ethanol yield were attributed to the small and well dispersed active components and the enhancement of CO dissociation.