Co/SiO₂ fiber catalysts were prepared by a sol-gel and electrospinning technique with impregnation method. Firstly, were prepared at the optimum condition, tip-to-collector distance (TCD) of 10 cm, applied voltage of 20 kV and needle size of 0.25 mm. The prepared fibers exhibited diameter of 491 nm analyzed and measured by SEM. Then, Co/SiO₂ fiber catalysts were prepared by impregnating a solution of cobalt nitrate at different metal loading such as 10, 15 and 20% and calcination. Finally, the fiber catalysts were characterized by XRD, TPR, BET, and SEM/EDS and comparing to the conventional porous catalysts and SiO₂ fiber that has smaller diameter of 329 nm. The obtained catalysts were tested in Fischer-Tropsch synthesis. The three parameters were observed such as temperature, support (porous and fiber) and cobalt content. Percent loading of cobalt were studied such as 10 15 and 20 indicated the higher %weight of cobalt the higher %CO conversion, but lower %selectivity CH4. The operated temperature in Fischer-Tropsch synthesis were 240 260 and 280℃. The most value of %selectivity CH4 was 280 ℃. When supports were studied the results revealed that porous catalyst has %CO conversion more than fiber catalyst. Finally, 10%Co/SiO₂ fiber catalyst diameter of 329 nm indicated the highest rate of reaction in Fischer-Tropsch synthesis.