The male erection is a complex process that involves multiple brain, hormonal, emotional, neurological, muscular and vascular issues. Impotence, also known as male erectile dysfunction, may be related to 1 or more of these causes. Male erectile dysfunction manifests itself in two ways: one is insufficient hardness for vaginal penetration of normal or too short duration; the other is sufficient hardness but too short duration to achieve sexual intercourse. Patients can meet the manifestations of both, or only one of them, to confirm the diagnosis, but the specific time and hardness are highly subjective, and the specific etiology needs auxiliary tests to determine. Ultrasound testing mainly detects penile cavernous structure and blood flow, and if necessary, cavernous injection of vasodilator drugs to observe the change of blood flow rate. Penile cavernosal perfusion test and penile cavernogram Penile cavernosal perfusion test and penile cavernogram can be used to check the function of venous leaky erectile dysfunction. In addition, if the secondary sexual characteristics are abnormally developed, it often indicates endocrine-generated erectile dysfunction due to primary or secondary hypogonadism and pituitary lesions. Poor palpation of the dorsalis pedis artery or loss of the bulbocavernosus muscle reflex and dull perineal sensation indicate the possibility of vascular or neurogenic erectile dysfunction. Therefore, the manifestation of impotence is mainly in the two aspects of hardness and time, but the diagnosis based on this is very subjective, to be specific to the cause and type will need to cooperate with the auxiliary examination.