Abstract: Objective To search differential gene expression in rats' hippocampus and to explore the molecular mechanism of brain injury caused by microwave.Methods The oligonucleotide gene chip of rat was used to screen for gene expression in rats' hippocampus after microwave radiation at an average power density of 30 mW/cm².Genes were functional classified by international standard.R T-PCR was used to identify.The interesting genes,and these genes were analyzed in the iniury of microwave.Results There were 13 genes differentially expressed after 6-hour radiation,4 genes up-regulated and 9 genes down-regulated,while 20 genes differentially expressed after 7-day radiation,4 genes up-regulated and 16 genes down-regulated.RT-PCR confirmed the results of gene chips.The genes were involved in metabolism,transport,signal,apoptosis,cell adhesion,transcription regulator,development,differentiation and so on.Conclusion There were some genes differentially expressed in rats' hippocampus induced by microwave,which provided new experimental references for the mechanism of microwave research.