A facile and scalable route, using the high-gravity reactive precipitation method which was carried out in a rotating packed bed (RPB) reactor, was proposed to synthesis alpha-Fe2O3 catalyst which is used to catalyze the decomposition of solid propellants. The effect of high-gravity level (G) of RPB reactor on the particle size and its distribution of alpha-Fe2O3 was explored. It was found that increasing the G of RPB is beneficial for the formation of alpha-Fe2O3 with smaller particle size and narrower size distribution. The alpha-Fe2O3 nanoparticles around 85 nm with narrow size distribution could be synthetized when G is higher than 120. The catalytic performance of the as-synthesized alpha-Fe2O3 on the thermal decomposition of ammonium perchlorate (AP) was performed by differential scanning calorimetric (DSC) method. DSC results show that adding 2 wt% as-prepared 84 nm alpha-Fe2O3 can decrease the temperature of low-temperature decomposition (LTD) and high-temperature decomposition (HTD) of AP by 14.4 degrees C and 53.4 degrees C respectively, and increase the heat released of AP's thermal decomposition process from 8641/g to 1235 J/g. Besides, result of DSC test and kinetic analysis indicated that the catalytic performance of alpha-Fe2O3 on the thermal decomposition of AP increased with lessening the average particle size of alpha-Fe2O3. (C) 2019 Published by Elsevier B.V.