Geriatric depressive disorder is a psychiatric disorder that first develops in old age and is characterized by a persistent depressive state of mind as the main clinical phase. The clinical features are dominated by depressed mood, anxiety, sluggishness and a wide range of somatic symptoms. The psychiatric disorder cannot be attributed to physical illness or organic brain disease. Depression is seen to be chronic, but often less typical than in young adults, with most patients experiencing lethargy, depression, decreased interest, loneliness, pessimism and despair. Most patients often express the experience of depression by saying “no energy” and “it’s hard to feel good”. Most patients have a long duration of illness, with a tendency to remission and relapse, and some patients have a poor prognosis. Some scholars in psychiatry believe that the first onset of depressive disorder in old age is an early clinical manifestation of primary degenerative brain disease. Of course, there are also biochemical metabolic abnormalities, premorbid personality basis, neuroendocrine changes, psychosocial factors and other etiological and pathogenetic bases. Investigations have shown an increasing trend of incidence. With the development of psychiatric disciplines, many scholars have found that there are many differences between the monophasic depressive disorders that develop in old age and those that develop in young adulthood, based on long-term clinical observation, combined with biological, psychological and sociological research, and believe that depressive disorders in old age may be a subtype of affective disorders. With the increase in life expectancy, there is a corresponding increase in the absolute number and proportion of elderly people suffering from depressive disorders, and depressive disorders have become one of the major problems that seriously affect the mental health of the elderly. The issue of pharmacological treatment of geriatric patients is tricky. Pharmacokinetic studies have shown that decreased p h and blood flow in the gastrointestinal tract of the elderly increases drug absorption. Due to the high fat content of the elderly, the drug is widely released in the body, and the declining liver and kidney function prolongs the elimination half-life of the drug and decreases the excretory capacity. The aging of the body, the nervous system becomes more sensitive to drugs, and other factors, if the same dose of antidepressant drug treatment, the effect of elderly patients than young adults, the same adverse reactions will also be significantly increased, so should be paid attention to in the clinic.