Objective To investigate the effects of long-term blood pressure variability on cognitive function in the hypertensive patients. Methods A total of 105 hypertensive patients were followed up once each month for 12 months, with blood pressure being measured by a specific person on each visit. Complete data were obtained for 97 patients. According to mini-mental state examination (MMSE) score, the patients were divided into the cognitive impairment group and the normal cognitive function group. After one-year follow-up, the patients were divided into cognition decline group (difference of MMSE ≥4 points) and cognition intact group. Statistical analysis was performed for the correlation of long-term blood pressure variability indices, MMSE score with long-term blood pressure variability. Data were processed by SPSS statistics 18.0.Results The systolic blood pressure(SBP), diastolic blood pressure(DBP), the standard deviation of SBP, and the coefficient of variation of SBP in the cognitive impairment group were all higher than those in the normal group. MMSE score was negatively correlated with long-term SBP, standard deviation of SBP and coefficient variation of SBP and DBP. The long-term SBP and DBP, standard deviation of SBP and DBP, coefficient variation of SBP, and DBP in the cognition decline group were all higher than those in the cognition intact group. Conclusion Long-term BPV may contribute to the occurrence of cognitive dysfunction in the hypertensive patients.