To study the protective mechanism of Danhong injection on brain microvascular endothelial cells (rBMECs) injured by hypoxic. In the experiment, primary suckling mouse's rBMECs cells were collected and identified with factor VIII to establish the 4 h injury model. Meanwhile, rBMECs were given Danhong injection (25, 50, 100 mL . L-1), and the superoxide dismutase (SOD) activity and the malonyldialdehyde (MDA) level were detected by the biochemical method. Cell MMP-9, ICAM-1 and P53 mRNA expression levels were detected by RT-PCR method. Changes in cells' microscopic structure were observed by transmission electron microscope. According to the results, primary rBMECs were notably injured by hypoxia. Compared with model group, Danhong injection (50, 100 mL . L-1) could remarkably resist the injury induced by hypoxic, increase intracellular SOD activity, decrease MDA level and significantly down-regulate ICAM-1, MMP-9 and P53 mRNA expressions. Danhong injection (100 mL . L-1) could protect the cells' normal morphology and microscopic structure, maintain the close intercellular junction, and inhibit the hypoxia-induced cell apoptosis. The results showed that Danhong injection plays a significant role in protecting rBMECs injured by hypoxia. Its mechanism may be related to the enhancement of cells' antioxidant capacity, the inhibition of inflammatory response and the cell apoptosis.