Background Hypertension (HTN) is a very prevalent public health problem and as the population ages,cognitive impairment (CI) is also going to be a public health burden.However,the relationship between hypertension duration and cognitive function declination worldwide is still unknown.The aim of the study was to investigate the effects of HTN duration on CI in Chinese population.Methods At baseline,1 386 HTN patients and 293 normotensive (NT) people were enrolled.The HTN patients were further divided into four subgroups (duration of HTN ＜6 years,6-10 years,11-20 years,and ＞20 years) according to the HTN duration and were screened for cognitive function with neuropsychological tests including mini-mental-state-examination (MMSE) and clock-drawing-test (CDT) in comparison with the NT group.Results More HTN patients had CI (45.3％) than NT subjects (30.4％),and increased with HTN duration (P＜0.000 1).Compared with the scores of MMSE and CDT in the NT group,the declines were higher in the HTN patients (P ＜0.000 1),and in the four HTN subgroups,both MMSE and CDT scores fall when the HTN duration increased (P ＜0.05).Furthermore,in the HTN population without CI,the trend in alteration of CI was relatively mild but still existed (P ＜0.05).Conclusion People with HTN are more likely to have CI and the possibility and aggravation increases the prolongation of HTN duration,both in amnesic and nonamnesic function.