Alzheimer's disease is a progressive neurodegenerative disorder causing irreversible deterioration in memory and loss of self-care ability, which is seriously affecting the quality of life. There is no cure for Alzheimer's disease. Medication only can control the progression of the disease. Early diagnosis and control of disease progress is of great significance in improving the quality of life of the patients and reducing the burden of family and society. Ophthalmic examination is seen as a window which can “see” brain directly, and some changes in the eye can reflect the changes of the brain most directly. This paper reviews the ophthalmic examination of Alzheimer's disease, including optical coherence tomography(OCT), visual field, contrast sensitivity and eye movements, et al. We hope to provide a new idea for the early diagnosis of Alzheimer's disease.