16.6%Co/γ-Al_2O_3 catalysts prepared by incipient wetness impregnation method were used for Fischer-Tropsch synthesis.The support was pre-treated with different concentration of NH_4NO_3 aqueous solution.The effect of support pre-treatment on the properties of support and performance of supported- cobalt-based catalysts was investigated.To treat the support with NH_4NO_3 aqueous solution enlarged the pore ofγ-Al_2O_3,decreased the impurity Na_2O content,and weakened the surface acidity ofγ-Al_2O_3. The change in the properties of the support decreased the interaction between cobalt species and support, enhanced the CO hydrogenation rate and the C_(5+)selectivity.For all catalysts,increasing the reaction temperature increased the CO hydrogenation rate or the CO conversion,slightly decreased the total hydrocarbon selectivity,and favored the formation of methane and light hydrocarbons,while the chain growth probability decreased.For 16.6%Co/γ-Al_2O3 catalysts,prepared with the support treated with 100 g/L NH_4NO3 aqueous solution,the CO conversion,the CH_4 selectivity,and the C_(5+)selectivity were 83.13%,6.86% and 82.75% respectively,and the chain growth probability was 0.83 under the condition of 493 K,1.5 MPa,500 h~(-1)and the molar ratio of H_2 to CO being 2.0 in feed. 16.6% Co / γ-Al 2 O 3 catalysts prepared by incipient wetness impregnation method were used for Fischer-Tropsch synthesis. Support was pre-treated with different concentration of NH 4 NO 3 aqueous solution. The effect of support pre-treatment on the properties of support and performance of supported-cobalt-based catalysts was investigated. To treat the support with NH 4 NO 3 aqueous solution enlarged the pore of γ-Al 2 O 3, decreased the impurity Na 2 O content, and weakened the surface acidity of γ-Al 2 O 3. The change in the properties of the support decreased the interaction between cobalt species and support, enhanced the CO hydrogenation rate and the C_ (5+) selectivity. For all catalysts, increasing the reaction temperature increased the CO hydrogenation rate or the CO conversion, slightly decreased the total hydrocarbon selectivity, and favored the formation of methane and light hydrocarbons, while the chain growth probability decreased. For 16.6% Co / γ-Al 2 O 3 catalysts, prepared with the support treated with 100 g / L NH 4 NO 3 aqueous solution, the CO conversion, the CH 4 selectivity, and the C 5+ selectivity were 83.13%, 6.86% and 82.75% respectively, and the chain growth probability was 0.83 under the condition of 493 K , 1.5 MPa, 500 h -1 and the molar ratio of H_2 to CO being 2.0 in feed.