The experimental sepsis conditions can cause a minor injury of the ultrastructure of the mitochondria in the astrocytes of the cerebral cortex of the rats. The biogenesis of the mitochondria in the astrocytes of the cerebral cortex of the rats was strengthened to cater for the increased demand for energy of the astrocytes under the sepsis conditions and finally recover the ultrastructure of the mitochondria with a minor injury. In response to the increased mitochondrial biogenesis, the activities of the mitochondrial fusion and fission of the astrocytes of the cerebral cortex of the rats were increased.