Abstract： Objective To investigate the effect of donepezil hydrochloride on changes of cognitive functions and Montreal cognitive assessment (MoCA) scores in patients with mild cognitive impairment (MCI). Methods A total of 50 patients diagnosed as having MCI,admitted to our hospital from September 2010 to March 2011, were recruited; these patients were randomly assigned into treatment group (treated with donepezil hydrochloride,n=30) and control group (treated with Ginkgo biloba,n=20); the changes of MoCA scores were noted at 12 and 24 weeks after treatment.The data were analyzed by the statistical software SPSS 10.0. Results MoCA scores of treatment group 12 and 24 weeks after treatment were significantly higher than those before treatment (P＜0.05); MoCA scores of treatment group were significantly higher than those of control group 12 and 24 weeks after treatment (P＜0.05).Mann-Whitney rank sum test showed significant improvement in digit span,verbal fluency and delayed memory after the treatment of donepezil hydrochloride for 12 weeks as compared with those before treatment (P＜0.05). Conclusion By MoCA scale,MCI patients could get early diagnosis; MCI patients with early diagnosis and early application of donepezil hydrochloride will delay their entry into the course of AD.