The pathological mechanism of depression is currently unclear, and a large number of studies have concluded that it is closely related to genetic, neurobiochemical, and psychosocial factors. Studies on genetic factors have revealed that patients with a family history are significantly higher than the general population, the closer the blood relationship, the higher the probability of the disease, and the mode of inheritance is polygenic in content. Neurobiochemical factors, a large number of studies have proved that the occurrence of depression is closely related to pentraxin, norepinephrine, dopamine, and γ-aminobutyric acid, etc. It can be seen through clinical medication, especially the application of pentraxin reuptake inhibitors, which have good therapeutic effects. Some studies suggest that the onset of depression is closely related to the above neurotransmitters. In addition, neuroendocrine factors, also have a relationship with the development of depression, especially involving hypothalamic-pituitary-adrenal related transmitter content. Psychological factors, among the factors of social development, are also important, especially for depressed patients, stressful life events, and early trauma, are closely related to the onset of depression.