Objective：To evaluate the association between mild cognitive impairment（MCI） and plasma homocysteine（Hcy） level through Meta analysis. Methods：Published literatures at home and abroad from 2003 to 2013 were searched through large literature databases，including PubMed，BIOsis Previews，Medline，EBSCO，CBM，CNKI，etc. The quality of studies was evaluated and data were extracted from studies.RevMan 5.2 software was used to do Meta analysis. Results：Eleven qualified control studies were identified，including 737 patients and 866 controls. The pooled standardized mean difference and 95% confidence interval of Hcy concentrations was 0.92（0.57，1.27），indicating higher Hcy levels in MCI patients. Funnel plot was symmetrical in general. Conclusions：Higher con－centration of plasma Hcy may be a risk factor of MCI. Prospective studies in the risk of developing MCI are needed，preferably in the form of cohort study and randomized controlled trials in large population.