Fischer-Tropsch synthesis was studied on mesoporous silica supported bimetallic Co-Ni catalyst in the fixed-bed reactor (FBR) and slurry continuous stirred tank reactor (CSTR) under different CO conversions by fixing other process parameters, for example, reaction temperature (300 degrees C), syngas ratio (2), and total pressure (3 MPa). The CO conversion is more sensitive in responding to the decrease of gas hour space velocity in FBR than that in CSTR. The intra-particle diffusional limitation was much improved in the CSTR system during Fischer-Tropsch synthesis due to the smaller particle size of the catalyst. The selectivity of gasoline fraction (C-5-C-13) was larger in CSTR than that in FBR when it was operated at relatively higher CO conversions (65%). The FBR tends to produce higher selectivity of longer-chain hydrocarbons than that in CSTR when the CO conversion was kept at around 22%. The increased 1-olefin selectivity was observed in both FBR and CSTR as CO conversion decrease with the FBR being more sensitive in responding to the CO conversion variation. The CSTR is found to be more effective in increasing light olefin fraction (C-2-C-6) when the CO conversion varies from 22 to 65%. (C) 2017 Curtin University of Technology and John Wiley & Sons, Ltd.