Men with diabetes mellitus may develop sexual impotence without prolonged active treatment, but the exact timing varies individually depending on the condition. Diabetes can cause peripheral vascular and neuropathy in severe cases, and penile erection is governed by blood supply and nerves. When peripheral vascular and neuropathy occurs, the blood vessels within the penis will become atherosclerotic and even occluded, nerves will be damaged, and sexual dysfunction such as impotence and premature ejaculation will eventually occur. If patients go to the endocrinology department early in the early stage of diabetes discovery and under the guidance of doctors for standardized treatment, complications can be effectively avoided and usually will not lead to sexual impotence. However, if patients do not treat the disease for a long time and let it develop, they may lose their sexual function after 2-3 months when the disease is serious. Therefore, diabetic patients should actively control their blood sugar, control their weight, adjust their blood sugar within a safe range through medication or diet, avoid foods with high sugar content, try to prevent complications, and insist on exercising to strengthen their physical fitness, which is more helpful for disease control.