【Abstract】 Objective To Investigate the characteristics of Cognitive function in elderly patients with mild cognitive impairment and its correlation with cerebrovascular reserve. Methods 30 patients with amnestic mild cognitive impairment (aMCI), 30 patients with vascular cognitive impairmemno dementia (VCIND), and 30 healthy people into aMCI group, VCIND group and control group were included in the present study. The mean blood flow velocity (MBFV) and breath holding time(BHI) were measured by transcranial doppler(TCD). The memory impairment was assessed by explicit memory Correlations of aMCI and VCIND with minimental state examination (MMSE) and montreal cognitive scores (MoCA) were analyzed. Results The MBFV and BHI in the control group were significantly higher than those in the aMCI group and the VCIND group (P＜005). There was no significant difference between the aMCI group and the VCIND group (P＞005). The scores of MoCA in the control group were significantly higher than those in the aMCI group and the VCIND group(P＜005). There was no significant difference between the aMCI group and the VCIND group (P＞005). The difference of MMSE between the three groups was not statistically significant (P＞005). There was no significant difference between groups MCI and VCIND in immediate recall (P＞005). The scores of delayed recall and delayed recognition in aMCI group were significantly lower than those in VCIND group and control group (P＜005). BHI was positively correlated with MMSE and MoCA scores (P＜005). Conclusion aMCI is mainly characterized by delayed recall and delayed recognition impairment. Impaired cerebrovascular reserve may be associated with mild cognitive impairment in patients with aMCI, and the use of TCD to detect MBFV does not distinguish between aMCI and VCIND, and BHI is important in the early diagnosis of brain microvascular lesions in patients with aMCI.