The invention discloses a magnetizing and roasting method of an iron oxide ore. The method comprises the following steps: adding a mixed material of which the fineness is -7mm to -10mm to a sealed reaction container, wherein the material comprises the following raw materials: 94.3%-97.1% of iron oxide ore, 1.8%-3.7% of a reducing agent bituminous coal and 1%-2.2% of a catalyst Na2CO3; 1 heating a container to 500 DEG C in a temperature rise zone, reacting C and O2 to generate CO2 and CO, and forming a weak reducing atmosphere by a reaction container; 2 heating a high-temperature zone to 820-850 DEG C, rapidly reacting CO and F2O3 under catalysis of Na2CO3 to generate CO2 and Fe3O4, dissociating Na<+> from Na2CO3, and prompting Fe3O4 crystalline grains to mix and grow; and 3 maintaining the temperature of a thermal insulation zone at 780-820 DEG C, finishing subsequent reducing reaction on CO and unreduced Fe2O3 in the step 2, and mixing the Fe3O4 in the step 3 with the Fe3O4 in the step 2 to grow. According to the method disclosed by the invention, the temperature of reducing reaction is divided into three zones, namely the temperature rise zone, the high-temperature zone and the thermal insulation zone, and full reducing reduction of the Fe2O3 is achieved, so that the magnetic susceptibility of the iron oxide ore is improved; and in addition, a catalyst Na2CO3 is capable of prompting the Fe3O4 crystalline grains to mix and grow; and the magnetic susceptibility is further improved.