SiO2-modified high thermal conductivity Al2O3@Al composites were synthesized and supported cobalt for Fischer-Tropsch synthesis to improve the catalytic performance and intensify the heat transfer within a fixed bed reactor. FTS results showed that the CO conversion and C5+ selectivity increased whereas CH4 selectivity decreased, which could be attributed to the reduced metal-support interaction via modification of SiO2 on the surface of Al2O3@Al. The heat transfer coefficients of the Co/SAl2O3@Al-x were more than 30 times those of conventional Co/Al2O3 according to the laser flash measurement. The thermal conductive study showed that a homogeneous radial temperature gradient was maintained within the catalyst bed for Co/SAl2O3@Al-x even without using a heat diluter, indicating good thermal conductivity within the reactor. In addition, the temperature of the catalyst bed for Co/SAl2O3@Al-x was easier to reach a "steady state" compared to the reactor packed with traditional low thermal conductive Co/Al2O3, which could improve the operating flexibility of FTS.