The purpose of this study was to investigate the effect of preadsorbed CO at different temperatures, calcination temperatures, the combined influence of reduction temperature and time, and pretreatment using hydrogen or syngas as reduc- tion agents on the F-T synthesis (FTS) activity and selectivity of Co/Al2O3 catalyst. The reactivity of the carbon species at higher preadsorption temperature with H2 in TPSR decreased, whereas the carbon-containing species showed higher reactivity over Co/Al2O3 catalyst with low calcination temperature. This agreed well with the order of catalytic activity for F-T syn- thesis on this catalyst. The catalytic activity of the catalyst varied with reduction temperature and time remarkably. CODEX optimization gave an optimum reduction temperature of 756 K and reduction time of 6.2 h and estimated C5+ yield perfectly. The pretreatment of Co/Al2O3 catalyst with different reduction agents (hydrogen or syngas) showed important influences on the catalytic performance. A high CO conversion and C5+ yield were obtained on the catalyst reduced by hydrogen, whereas methane selectivity on the catalyst reduced by syngas was much higher than that on the catalyst reduced by hydrogen. The purpose of this study was to investigate the effect of preadsorbed CO at different temperatures, calcination temperatures, the combined influence of reduction temperature and time, and pretreatment using hydrogen or syngas as reduc tion agents on the FT synthesis (FTS) activity and selectivity of Co / Al2O3 catalyst. The reactivity of the carbon species at higher preadsorption temperature with H2 in TPSR decreased, whereas the carbon-containing species showed higher reactivity over Co / Al2O3 catalyst with low calcination temperature. This well was with the order of catalytic activity for FT syn-thesis on this catalyst. The catalytic activity of the catalyst varied with reduction temperature and time remarkably. CODEX optimization gave an optimum reduction temperature of 756 K and reduction time of 6.2 h and estimated C5 + yield perfectly. The pretreatment of Co / Al2O3 catalyst with different reduction agents (hydrogen or syngas) showed important influences on the catalytic perfor mance. A high CO conversion and C5 + yield were obtained on the catalyst reduced by hydrogen, nar methane selectivity on the catalyst reduced by syngas was much higher than that on the catalyst reduced by hydrogen.