Objective To explore the clinical significance of interleukin pathological physiologic process and treatment following in patients with pulmonary tuberculosis. Methods The serum levels of IL-2, IL-10, IL-17 and IL-18 in 215 patients with pulmonary tuberculosis before and after therapy and 60 controls were determined by ELISA. The sputum bacteria trans-negative rate and effective rate were analyzed in patients after therapy. The diagnostic effective comparison of single and multi interleukin was carried out by determining sensitivity, specificity and accuracy. Results Before therapy, the serum IL-2 and IL-10 levels in patients with pulmonary tuberculosis were significantly lower than those in 60 controls (P<0.01), but the serum IL-17 and IL-18 levels were significantly higher (P <0.05). After therapy the serum IL-2 and IL-10 in patients with pulmonary tuberculosis were significantly increased (P <0.05), the serum IL-17 levels was decreased (P <0.05) and the serum IL-18 levels was return normal (P >0.05). The sputum bacteria trans-negative rate and effective rate in patients with pulmonary tuberculosis after therapy was 87.00% and 92.1% respectively. The diagnostic value of single interleukin was low. The sensitivity, specificity and accuracy of combination determination of four interleukin were 69.8%, 65.0% and 72.0% respectively. Conclusion The interleukin may take part in pathological physiologic process and is valuable index before and after therapy in patients with pulmonary tuberculosis.