Age-related diseases have become more and more dominant with the coming era of aging. Elderly patients with mild cognitive impairment (MCI) are of high risk of Alzheimer's disease (AD). MCI is regarded as a clinical stage between normal cognitive aging and mild dementia. However, very little is known on how to recognize MCI in routine clinical practice. Strengthening the knowledge of early MCI, and improving its assessment and screening in the elderly can guarantee early intervention and prevention of AD.