The probability of recurrence of old tuberculosis is relatively small, generally after standardized treatment, the probability of recurrence of old tuberculosis within five years is less than 5%. Old tuberculosis refers to the imaging manifestations left in the lungs after the patient has a history of previous tuberculosis or occult Mycobacterium tuberculosis infection, and is cured or self-healed. The prognosis for old TB is good, but obstructive lung disease complicates 1/3 of patients. It is important to note that if there is a history of active TB but no standardized treatment for TB, it is necessary to refer to the standardized treatment for TB, and the prognosis is better after treatment, with less than 5% of patients relapsing within five years. The probability of recurrence of old tuberculosis is relatively small, generally after standardized treatment, the probability of recurrence of old tuberculosis within five years is less than 5%. Patients with old TB should pay attention to strengthening nutrition and treating comorbidities, such as diabetes and hyperthyroidism. This is because severe underlying diseases can lead to a decrease in resistance, which increases the probability of recurrence of old tuberculosis.