Erectile dysfunction (ED), commonly known as impotence, is a common and prevalent disease that plagues the majority of male friends and is defined as the inability to get an erection or maintain an erection to achieve a satisfactory sexual life. Erectile dysfunction is divided into: psychological, neurological, arterial, venous, endocrine ED, and its differential examination methods are complex, we condensed and expressed as follows: I. Differential examination of psychological and organic erectile dysfunction: 1. nocturnal erection test (NPT) 2. penile hardness test (RIGISCAN) 3. intracavernosal injection test (ICI) II. Differential tests for neurogenic erectile dysfunction: 1, somatosensory evoked conduction of the dorsal penile nerve (SSEP) 2, sciatic cavernous reflex (ICR) 3, bulbocavernosus reflex (BCR) 3, differential tests for vascular erectile dysfunction: 1, penile cavernosal Doppler 2, penile cavernosography 3, penile arterial blood pressure/brachial artery systolic pressure (PBI) 4, differential tests for endocrine erectile dysfunction 1.Sex hormone tests, including folliculogenic hormone (FSH), luteinizing hormone (LH), estradiol (E2), progesterone (P), testosterone (T), prolactin (PRL) 2.Glucose and glucose tolerance test, thyroid function, pituitary function test, etc.