Diabetes does not cause tuberculosis, but diabetics are susceptible to tuberculosis infection. Tuberculosis is an infectious disease of the respiratory system caused by Mycobacterium tuberculosis infection, and the spread of infectious diseases requires an infectious source, an infectious route and a susceptible population. Because of the long-term elevated blood sugar of diabetic patients, it is easy to lead to poor body resistance and complicate various bacterial infections, including Mycobacterium tuberculosis infection. Therefore, diabetic patients belong to the susceptible group of Mycobacterium tuberculosis, and when diabetic patients come into contact with sputum and other secretions of tuberculosis carriers, they are easily infected with tuberculosis. Therefore, diabetes does not cause tuberculosis, but diabetic patients are very susceptible to tuberculosis infection. When diabetic patients are infected with pulmonary nodules, they are more likely to spread and harder to control than non-diabetic patients. Therefore, when diabetic patients have pulmonary tuberculosis, it is necessary to increase the types of combination drugs and prolong the course of treatment appropriately when carrying out anti-tuberculosis treatment.