This study showed that cerebral ischemia–reperfusion increased the expression of mitochondrial fission‐related protein Fis 1 and decreased expression of mitochondrial fusion‐related proteins MFN1, MFN2, and OPA1 in mice brain, resulting in mitochondrial dynamics disorder and structural damage, aggravating neuronal apoptosis and neurological impairment. This evidence concerns the gene MFN1 and brain ischemia.