Abstract: Long chain alcohols (C+ mixed-alcohols) are recognized as important feedstocks for the production of fine chemicals such as detergents,lubricants and dispersants. Synthesis of long chain alcohols directly from syngas via Fis- cher-Tropsch synthesis (FTS) route has attracted a great attention at present. In the crude product of FTS,unsaturated compounds involving alkenes and aldehydes coexist with alcohols and paraffins accompanying with some organic acids, and a hydrofining of which is necessary for the subsequent separation process. A Pd-based catalyst supported by acti- vated carbon (AC) was prepared and evaluated in a packed-bed reactor under the conditions of 6 h-1 liquid-hourly speed velocity (LHSV),100-300 hydrogen-oil ratio,100-310 ℃ and 8 MPa. At temperatures higher than 250 ℃ ,the conversion of unsaturated compounds exceeded 99% and most of the acids ( >90% ) were removed. Whereas a further increase of temperature (higher than 270 ℃ ) resulted in the decrease of alcohol yield due to the hydrogenolysis of al- cohols. Accordingly,the most suitable reaction temperature should be kept at about 250 ℃ for the highest alcohol yield. Active site structure involving crystalline phase and particle size of the catalyst before and after reaction was characterized by X-ray radical diffraction (XRD) method,and the Pd nanoparticles were identified as the active site which remained almost unchanged after reaction,indicating that the structure of active site stayed stable in the run. Based on the lab-scale results,the catalyst was successfully utilized in the hydrofining plant of the 10 kt / a grade in- dustrial demonstration of long chain alcohol synthesis from syngas in Yulin,China after the procedures including a 1 000 hour life test and a large scale preparation. Hydrofining product composed by alcohols and paraffins was synthe- sized under the conditions of 250 ℃ and 8. 4 MPa,in which the conversions of unsaturated components and acid reached 100% and 90. 4% ,respectively. The study paves the way for the designation and construction of an alcohol- paraffin separation unit.