【Abstract】Objective To observe the clinical efficacy of thymosin combined with standard regimen in the treatment of refractory pulmonary tuberculosis and its effect on serum MMP9 and sTREM1 levels.Methods Two hundred and thirty patients with MDRTB from January 2014 to October 2015 were randomly divided into control group and study group with 115 cases in each group. The control group was treated with 6ZVAmPtoPAS/18 ZVPtoPAS and the study group with 6ZVAmPtoPASCS thymosin / 18 ZVPtoPASCS. The clinical efficacy, incidence of adverse reactions and serum MMP9 and sTREM1 levels were observed in the two groups.The patients in both groups were treated with gluconolactone tablets during the treatment period.Results The cure rate of the study group was significantly higher than that of the control group (P＜005). Before treatment, there was no significant difference in serum MMP9 and sTREM1 levels between the two groups (P＞005). After treatment, the serum levels of MMP9 and sTREM1 in the two groups were significantly decreased, but the degree of decrease in the study group was significantly higher than that in the control group (P＜005). There was no significant difference in the incidence of adverse reactions between the two groups (P＞005). Conclusion Thymosin combined with 6VZthKP/18VZthP has a better effect on patients with refractory pulmonary tuberculosis. It can significantly improve the immunity of patients, improve the prognosis of patients, reduce their inflammatory reaction, and there is no serious adverse reaction, so it is worth popularizing in clinic.