Objective: To investigate the alteration of red cell deformability (RCD) and adenosine triphosphatase (ATPase) activity of cell membrane in essential hypertensive (EH) patients and essential hypertension patients complicated with cerebral infarction (HCI). Methods: Twenty healthy individuals, 30 EH patients and 30 HCI patients were selected as subjects. The erythrocyte deformability indexes (DI)、 Na+, K+-ATPase and Ca2+ATPase activities were examined. Results: (1) EH patients had significantly higher DI, lower ATPase activity as compared to healthy individuals. There were significantly negative correlation between DI and ATPase activity, and a significantly positive correalation between DI and diastolic blood pressure in EH patients; (2) There was significantly higher DI, lower ATPase activity in HCI patients than those in EH patients. There was significantly negative correlation between DIand ATPase activity in HCI patients. Conclusion: (1) RCD decreases in EH patients, and RCD is correlated to the decreased ATPase of cell membrane and elevated blood pressure; (2) The decreased RCD level may be related to the occurrence of HCI.