A very soft penis usually refers to erectile dysfunction, including physiologic and pathologic. Pathologic causes such as penile-related diseases, neurological factors, vascular factors, endocrine factors and so on. 1. Physiological causes: such as tension, anxiety or excessive pressure. For example, the husband and wife relationship is not harmonious, lack of sexual knowledge, life and work or economic pressure and so on. 2. Pathological reasons (1) Penis-related diseases: common diseases include sclerodactyly, small penis, hypospadias, severe penile, penile trauma, etc. (2) Neurological factors: central and peripheral nerve diseases or injuries, etc. Central diseases include multiple sclerosis, Parkinson’s disease, stroke, spinal cord lesions, etc.; peripheral neuropathy, such as diabetes mellitus, polyneuropathy, etc. (3) Vascular factors: vascular lesions are the main cause of erectile dysfunction, including diseases that may lead to reduced blood flow in the penile cavernous artery, such as atherosclerosis, arterial injury, arterial stenosis, pubic artery shunt, etc., as well as impede the venous return to the closed mechanism of the penile tunica albuginea, the penis cavernous sinus of the penile venous leakage due to the reduction of smooth muscle. (4) Endocrine factors: such as hypogonadotropic hypogonadism, hyperprolactinemia, hyper or hypothyroidism, hyper or hypogonadotropic adrenal cortical function, etc., can cause erectile dysfunction. (5) Other: drug-induced factors, including anti-hypertensive drugs, antidepressants, antipsychotics, anti-androgens, etc. In addition, major surgeries such as radical prostate cancer treatment, pelvic or retroperitoneal radiotherapy can also lead to erectile dysfunction. It is recommended to go to the hospital in time, to clarify the cause of the disease, and then carry out active treatment.