Secondary tuberculosis is active tuberculosis that occurs once again after a previous infection with Mycobacterium tuberculosis has been cured or after Mycobacterium tuberculosis infection has been quiescent for a period of time. The causes of secondary TB are endogenous and exogenous. Endogenous recurrence is that the patient has been infected with Mycobacterium tuberculosis and formed latent foci in the lungs, and when the patient’s resistance decreases, the foci recur and active tuberculosis appears again. Exogenous reinfection is when the patient’s resistance declines and is re-infected after coming into contact with exogenous Mycobacterium tuberculosis. Clinical symptoms of secondary tuberculosis include coughing, coughing up sputum, hemoptysis, low-grade fever, night sweats, and fatigue, etc. The main treatment methods are drug treatment and surgery. Anti-tuberculosis drugs include pyrazinamide and ethambutol. Patients with ineffective drug treatment and hemoptysis can be treated with surgery to remove the diseased lung. Patients with secondary tuberculosis should strictly follow the doctor’s instructions, and under the doctor’s guidance, early, regular, combined, and the whole process of anti-tuberculosis treatment. Regular review, observation of changes in the condition, timely adjustment of the treatment program.