Abstract Background To determine whether items of the Chinese version of the Montreal Cognitive Assessment Basic (MoCA-BC) could discriminate among cognitively normal controls (NC), and those with mild cognitive impairment (MCI), mild Alzheimer’s disease (AD), and moderate-severe (AD), as well as their sensitivity and specificity. Methods MCI (n = 456), mild AD (n = 502) and moderate-severe AD (n = 102) patients were recruited from the memory clinic, Huashan Hospital, Shanghai, China. NC (n = 329) were recruited from health checkup outpatients. Five MoCA-BC item scores were collected in interviews. Results The MoCA-BC orientation test had high sensitivity and specificity for discrimination among MCI, mild AD and moderate-severe AD. The delayed recall memory test had high sensitivity and specificity for MCI screening. The verbal fluency test was efficient for detecting MCI and differentiating AD severity. Conclusions Various items of the MoCA-BC can identify MCI patients early and identify the severity of dementia.