The harm caused by smoking to diabetes is as follows: 1, tobacco contains nicotine and carbon monoxide, which can cause damage to the blood vessel wall and intima. Therefore, smoking can increase the incidence of diabetic macroangiopathy and atherosclerosis; 2. Smoking can aggravate the appearance of proteinuria in diabetic patients and increase the risk of proteinuria appearance by about 4.5 times. Therefore, it can cause and aggravate the occurrence of nephropathy and even uremia, increasing the chance of death; 3. Diabetic patients have poor resistance to infection, and smoking can cause a weakening of the respiratory mucosal barrier, making them susceptible to infection and not easily controlled.