To evaluate the clinical diagnostic criteria of mild cognitive impairment (MCI) and the function of clinical memory scale (CMS), seventeen neuropsychological tests such as CMS were performed in 34 subjects complaining of memory decline. The subjects were divided into MCI group and control group according to the results of tests. The speciality and sensitivity of MCI combined with its clinical significance were tested by cluster analysis. The results showed that fifteen of 34 subjects were diagnosed as MCI with 100% sensitivity, zero ? error, 67 86% speciality and 32 14% misdiagnostic rate. The results indicate that the diagnostic criteria of MCI are basically practicable and CMS may be used to diagnose MCI.