The effect of different original composition of iron oxide in the precursor on the reduction performance of ammonia synthesis catalyst was studied by thermal analysis. The precursor phase composition of the catalyst produces an effect on reduction performance

which is similar with the effect on activity. In the case of two phase coexistence in the precursor

the reduction process of catalyst is divided into sequential stages with respect to phase

which obeys the competitive reduction mechanism. It results in slower reduction rate

higher reduction temperature and decreasing catalyst activity. The reduction performance of ammonia synthesis catalyst is consistent with its activity

the easier the catalyst reduction

the higher is the activity. The experimental results indicate that Fe1-xO based catalyst has the fastest reduction rate

the lowest reduction temperature and the highest activity among all the fused iron catalyst for ammonia synthesis.