Patients with tuberculosis combined with diabetes mellitus have a good prognosis with timely and standardized anti-tuberculosis treatment and effective control of blood glucose, which generally does not affect life expectancy. Tuberculosis can be cured, but diabetes requires lifelong medication, and the prognosis is poor for patients with severe disease, poorly controlled diabetes, irregular treatment, and combined drug resistance. Tuberculosis bacteria may not be effectively controlled and may spread within the lungs or even through the blood or lymphatic tract to the whole body to form extrapulmonary tuberculosis, the most serious of which is tuberculous meningitis, which has the highest death rate. If patients adhere to regular anti-tuberculosis treatment without strict dietary control or are unwilling to comply with medical advice to switch to insulin to lower blood sugar, resulting in poor glycemic control, the control of tuberculosis will also be affected at this time, and the repair of tuberculosis lesions will be slow or aggravated, and drug resistance may even occur. Poor blood glucose control also makes it easier to cause various diabetes complications, which can lead to aggravation of the disease and seriously affect the quality of life of patients and shorten their life span.