Abstract: Mineralogical studies on catarinite raw ore and reduced samples at different temperatures were carried out, and phase transformation was explored in the catarinite selective reduction roasting process. The results show that the main metal minerals in the catarinite are limonite and then hematite. The distribution of Ni in Mn-free iron minerals is relatively homogeneous, but it is relatively concentrated in Mn-contained iron minerals, and Ni is associated with Mn. Reduction, phase transformation, migration and enrichment of Fe, Ni and Co gradually occur in the process of catarinite reduction roasting with increasing temperature, so the selective reduction roasting temperature should be controlled strictly. To reduce Ni, Co and Fe selectively and form a more Ni and less Fe alloy phase and magnetite, 750℃ is a proper roasting temperature, at which the formed alloy phase contains Ni of 55. 55%, Co of 9. 86% and Fe of 33. 99% averagely, the metal conversion rate of Ni is 88. 49%, and the iron oxide is mainly magnetite.