Abstract: In order to develop an air purification technique in accordance with the biosafety requirements for the spacecraft sealed cabin, we carry out experiments to study how the microwave radiation. inactivates different bioaerosols with and without the additive Fe₃O₄ ceramsite as the microwave absorbing material. It is shown that for each kind of bioaerosols, the inactivation rate increases with the microwave radiation time. The inactivation rates for different bioaerosols by the microwave radiation are ranked in descending order: Escherichia coli, Aspergillversicoir, Bacillus subtilis, Bacillus subtilis spore. The mechanism of the increased inactivation rate by the microwave radiation on the bioaerosols with Fe₃O₄ ceramsite involves a combination of the microwave thermal effect, the non-thermal effect, and the oxidation of O• and •OH free radicals. The microwave effect with the existence of the Fe₃O₄ ceramsite can reduce the unit microwave energy consumption by 48.56% to 59.23%. The microwave radiation with the help of the Fe₃O₄ ceramsite can be effectively applied in the air purification process for China’s manned spacecraft (including the space station).