The invention relates to a method for preparing active iron oxide powder materials by means of vacuum aluminothermic reduction. Iron sesquioxide micro-powder is used as a raw material, aluminum micro-powder is used as a reducing agent, and the iron oxide powder materials can be manufactured by the aid of a vacuum aluminothermic reduction process. The method includes preparing steps of 1, uniformly mixing the iron sesquioxide micro-powder, namely, the raw material, and the aluminum micro-powder, namely, the reducing agent, with each other to obtain mixtures for standby application; 2, placing the mixtures obtained in the step 1 in the center of a clean porcelain boat; 3, placing the porcelain boat prepared in the step 2 in the middle of a high-temperature tube furnace, sealing the tube furnace, pumping the high-temperature tube furnace by the aid of a vacuum pump to enable the high-temperature tube furnace to be in an internal negative-pressure state and keeping the vacuum degree of the high-temperature tube furnace lower than or equal to 5pa; 4, heating the high-temperature tube furnace until the temperature of the high-temperature tube furnace reaches 900-1000 DEG C, keeping the raw material and the reducing agent reacting to each other for certain reaction time, then stopping heating the high-temperature tube furnace, cooling the high-temperature tube furnace until the temperature of the high-temperature tube furnace reaches the room temperature and taking products out of the high-temperature tube furnace. The method has the advantages that technologies are simple and controllable, prepared active iron oxide (FeO/Fe<3>O<4>, FeO, Fe/FeO) powder is high in purity and low in cost, and requirements of actual production can be met.