Erectile dysfunction is when a man’s penis fails to become erect at the critical moment, and its causes are mainly physiological and pathological factors. Physiological factors include age, psychological stress, etc. Pathological factors are mostly seen in cardiovascular disease, diabetes and hypercholesterolemia and other chronic underlying conditions, chronic prostatitis, chronic liver and kidney insufficiency, etc., and need to improve the examination, in order to clarify the cause. 1. Physiological factors: with age, the patient’s body androgen level decreases, libido and sexual function decline, so it is easy to appear erectile dysfunction; when the psychological pressure is too large or when the mood is tense erectile dysfunction is easy to appear, such as the first time sexual life of the male, easy to because of the nervousness can not be erected. 2. Pathological factors: such as atherosclerosis can affect the blood supply to the penis; diabetes and hypercholesterolemia patients, not only can affect the patient’s nerves can also affect the peripheral blood vessels, which in turn cause erectile dysfunction; patients with chronic prostatitis are prone to not be able to get an erection, considering that patients with the existence of depression, anxiety and so on; chronic liver and kidney insufficiency of the patient can also appear erectile dysfunction. Erectile dysfunction may also be caused by other factors, it is recommended that patients go to a regular hospital, complete the auxiliary examination, in order to clarify the cause of the disease, and then by a professional physician for the cause of the appropriate treatment, and strive for early recovery.