The invention relates to a method for producing iron concentrate powder by using a reductive magnetizing rotary furnace. The method comprises the following steps of: fully mixing 3 or 5 weight percent of reducing carbon with granularity of less than or equal to 5 millimeters and 97 or 95 weight percent of limonite powder with granularity of less than or equal to 10 millimeters and grade of 45 percent to obtain powder; delivering the powder to the magnetizing rotary furnace, delivering the burning coal gas generated by a coal gas producer to the magnetizing rotary furnace to roast the powder in the furnace, performing attached water removal, the reaction being: Fe2O3.nHO2O(H2O)+heat-> Fe2O3.nH2O+H2O, crystallization water removal, the reaction being: Fe2O3.nH2O+heat-> Fe2O3.nH2O and reductive magnetization, the reaction being: C+6Fe2O3->4Fe3O4+CO2+heat at the temperature of between 600 and 900 DEG C, delivering dust-containing smoke to a smoke chamber outside the furnace from the magnetizing rotary furnace, performing five-stage dust removal, collecting dust, and exhausting tail gas; delivering the powder calcined by the magnetizing rotary furnace to a cooler, and performing water quenching to obtain finished limonite powder with grade of 56 percent; and sequentially delivering the finished limonite powder to a ball mill and a magnetic separator, and finally obtaining the iron concentrate powder with grade of 60 percent.