The process of penile erection is essentially a series of neurovascular activities, and the degree of erection depends on the balance between arterial inflow and venous outflow. The penile Doppler ultrasound blood flow test is precisely designed to detect the arterial and venous blood flow in the penis. The principle is to detect the arteries and veins of the penis using color Doppler ultrasound in the case of erection, regardless of the diagnosis of arterial or venous ED. Main use: Diagnosis of vascular erectile dysfunction. Method: By making the subject’s penis fully erect through self-erection or drug erection, the physician will place the ultrasound probe on the body of the penis for testing, and give diagnosis and treatment after data is obtained. The test indexes include: maximum systolic blood flow rate (PSV), diastolic blood flow rate (EDV), resistance index (RI), etc. Precautions: ① The subject should make an appointment for operation; ② Before the examination, you should explain your usual erectile function and ejaculatory latency to the physician; ③ After the examination, leave the hospital under the guidance of the physician; ④ Actively cooperate with the physician and take care of the instrument.