Abstract: Magnesium-promoted Fe/Cu/K/SiO2 catalyst for Fischer-Tropsch synthesis (FTS) was prepared using spray-dried technology. The structures of the catalysts after calcination at different temperatures were characterized by means of N2 physisorption, X-ray diffraction (XRD), Mö ssbauer spectroscopy (MES), and H2 temperature-programmed reduction (TPR). It showed that increasing calcination temperature decreased the BET surface area and increased the average pore diameter and the size of α-Fe2O3 crystallite for the catalyst, leading to a difficult reduction of the active phase. The Fischer-Tropsch performance of the catalysts after calcination was tested in a fixed bed reactor under the conditions of 250 ℃, 2.0 MPa and 2 000 h－1. With the increase of the calcination temperature, the initial activity of the catalyst decreased, and the activity gradually approached to a stable value with time on stream, depending on the induction period which prolonged with increasing calcination temperature. Additionally, the increase of the calcination temperature also favored the formation of heavy hydrocarbons and declined the CH4 selectivity.