The effects of reduction temperature and reaction temperature, pressure and space velocity on iron-based K/FeCuAlO (x) Fischer-Tropsch catalysts prepared by co-precipitation were investigated. The catalyst reduced at 150 A degrees C deactivated quickly due to an abundance of unreduced iron species. With increasing reduction temperature, the iron oxide's phase transformed from hematite (alpha-Fe2O3) to magnetite (Fe3O4) and finally to metallic iron (alpha-Fe). The induction period to reach steady-state catalytic activity was reduced at increased reduction temperatures due to in situ reduction by syngas during reaction. CO conversion increased with increasing reaction temperature, and selectivity to C-5+ decreased with increasing reaction pressure and space velocity. At reaction temperatures up to of 300 A degrees C, CO2 formation by the water-gas shift reaction was linearly correlated with the extent of CO conversion, and CO2 formation was slightly suppressed at a parts per thousand yen350 A degrees C by a reverse water-gas shift reaction.