【Abstract】 Objective To investigate the expression and significance of 5lipoxygenase (5-LO) in the cerebral artery smooth cells of spontaneously hypertensive rats (SHR). Methods 16 weeks old male 15 SHR rats and 15 WKY rats were selected in the present study. The expression of 5-LO in cerebral artery was detected by immunofluorescence. Transmission electron microscopy was used to observe the performance of arterial intimal. ELISA was used to detect the expression of 5-LO in serum and artery. Results The artery intimal of WKY rat was smooth. The smooth muscle cells of WKY rat orderly arranged without hyperplasia. The endothelial cell of SHR rat was swelled. The smooth muscle cell of SHR was hypertrophy disorder. The fluorescence intensity of 5-LO in rat cerebral artery smooth muscle cells of SHR rat (110.93±5.92) was significantly stronger than that of WKY rats (P<0.05). The levels of 5-LO in serum and cerebral artery of SHR rats were significantly higher than that of WKY rats (P<0.05)。Conclusion The expression of 5-LO in rat cerebral artery smooth muscle cells and blood are abnormal increased, which may play a role in the course of hypertensive cerebral vascular damage.