Using flow chamber system, we quantitatively studied the adhesion of erythrocytes (RBCs) of patients with cerebral thrombosis (CTh) to cultured human umbilical vein endothelial cells (HUVECs) treated with H2O2. The results showed that injured HUVECs enhanced adhesion of RBCs to HUVECs in patients with CTh. There is injury of endothelial cells in the pathogenetic and pathologic process of CTh, and the adhesion of RBCs to ECs promotes vaso-occlusive and vascular damage; thus the adhesion of RBCs to injured ECs might play an important role in the pathogenesis and pathologic process of CTh.