Abstract: Objective: To observe the morphologic and aggregative changes of erythrocyte in hypertension and to evaluate the significance of the changes. Methods: Two groups were studied; Group 1 consisted of 30 hypertensives.This group was of medium risk according to WHO and ISH （1999） without diabetes, coronary heart disease, hyperlipoidemia.Group 2 was made up of 10 healthy subjects, venous blood specimens were examined by scanning electronic microscope（SEM） and transmissible electronic microscope （TEM）.Erythrocyte specific surface was measured by quadratic test grid. Results: Under SEM, percentages of stoma-tocyte, ridgecyte and spherocyte-like erythrocyte in hypertension patients decreased significantly（P＜0.05）.Under TEM, the percentages of dumbbell-like erythrocyte in hypertension are decreased significantly, The erythrocyte specific surface of hypertensive group is smaller than that of control group（P＜0.05）.Under TEM and SEM, there is a increase in erythrocyte aggregation in hypertension, especially in which with left ventricular hypertrophy. Conclusions: The percentages of erythrocyte with abnormal shape in hypertension increase,and erythrocyte specific surface of hypertensives are decrease.There is a increase in erythrocyte aggregation in hypertension, especially in which with left ventricular hypertrophy.