To explore the relationship between apolipoprotein E polymorphism and cognitive function in primary hypertension patients, we collected 200 Chinese primary hypertensive patients. Blood pressure (BP), heart rate (HR), height, body weight, waistline, hip circumference were measured. The Mini Mental State Examination (MMSE) was applied to test the cognitive function and compute score. Full-automatic bio-chemistry analyzer was used to determine total cholesterol (TC) and triglyeride (TG) and fasting glucose. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RELP) was used for the analysis of the apolipoprotein E polymorphism. We found that in primary hypertension patients, the genotype frequency of epsilon3/4 and epsilon4/4 were significantly higher in the cognitive impairment group than that in the cognitive normal group. The allele frequency of e4 is obviously higher in the cognitive impairment group than that in the cognitive normal group. Age and epsilon4/4 genetype were positively correlated with hypertensive-cognitive impairment, while cultural level was negtively correlated with it. ApoEepsilon4 allele and age might be risk factors for the cognitive impairment in hypertensive patients. The epsilon4 homozygote (epsilon4/4) might be an important influencing factor for the progression of cognitive impairment.