Geriatric psychiatry is a branch of psychiatry for the diagnosis and treatment of mental disorders occurring in the elderly. Geriatric psychiatry involves health promotion and disease prevention strategies in both biomedical and behavioral areas. Geriatric psychiatry is dedicated to promote the mental health and well being of older people and improving the care of those with late-life mental disorders, including typical dementia, depression, anxiety, late-life psychosis, and sleep disorder. Patients with chronic pain, Parkinson's disease, heart disease, diabetes, stroke or other medical disorder are also cared by geriatric psychiatrists. Older adults have special physical, emotional and social needs. Therefore, the therapeutic guideline in geriatric psychiatry should be established through a multidisciplinary approach encompassing disease diagnosis, treatment, prevention, and rehabilitation, ultimately to improve the quality of life.