Basing on the prevalence survey, 94 cases were diagnosed as simple senile systolic hypertension and 67 cases as non simple senile systolic hypertension, and 136 persons with normal blood pressure were sampled as control. Two case-control studies were conducted, then the etiologic factors of two types of hypertension were compared. Among age, sex, smoking, drinking, mental incidence, family history of hypertension, body height, body weight, body weight index, blood sugar, TC, TG, HDL-c, etc., a total of 18 factors, mono variate unconditional logistic regression analysis showed that the occurrence of ISH associated with age, family history of hypertension, mental incidence and blood sugar, and that the risk factors of NISH were body weight index, body weight, smoking, drinking, mental incidence, and TC. Further multi-unconditional logistic regression turned out that mental incidence, family history of hypertension and blood sugar entered the model of ISH, and that the body weight index, smoking, mental incidence, blood and TC entered the model of ISH. The study showed that the etiologic factors of ISH differed from those of NISH, which was a syndrome differed from NISH.