Objective To observe the damaging effect of microwave on neurons and the protective effect of selenium on damaged neurons after exposure to microwave. Methods In vitro cultured PC12 cells were exposed to 65 mW/cm 2 microwave. The survival rate, SOD activity, GSH-Px activity, and MDA concentration of PC12 cells were detected. The effects of selenium on PC12 cells after exposure to microwave were reflected by these markers. Results Survival rate, activity of superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activity of PC12 cells decreased, but malondialdehyde (MDA) concentration of PC12 cells increased after microwave radiation. These changes weakened when PC12 cells were exposed to microwave after pretreatment with selenium. This effect was more significant after pretreatment with selenium at the high dose. Conclusion PC12 cells can be damaged by microwave through peroxidation. Selenium pretreatment can promote the antioxidation and protect PC12 cells from damages induced by microwave.