Abstract： Objective To investigate drug resistance and clinical efficacy of second-line anti-tuberculosis drugs in patients with multidrug-resistant pulmonary tuberculosis.Methods A total of 183 multi-drug resistant pulmonary tuberculosis (MDR-PTB) patients received standard anti-tuberculosis treatment in Zhejiang Provincial Center for Diagnosis and Treatment of Tuberculosis during March 2011 and March 2013.Patients were divided into four groups according to the results of first-line anti-tuberculosis drugs susceptibility test:group A (n =30) resistant to isoniazid (H) and rifamipicin (R) ; group B (n =28) resistant to HR and ethambutol (E) ; group C (n =53) resistant to HR and streptomycin (S) ; groups D (n =72) resistant to HRES.Drug susceptibility tests of second-line drugs kanamycin (Km),protionamide (Pto),paraaminosalicylic acid (PAS) and levofloxacin (Lfx) were performed.Negative conversion rates of mycobacterium tuberculosis in sputum culture were also observed and compared among different groups with x2 test.Results Among 183 MDR-PTB patients,49 cases (26.8％) were resistant to Lfx,which was significantly higher than that of Km (8.7％,n =16),Pto (13.1％,n =24) and PAS (6.6％,n=12) (x2 =37.983,P＜0.05).The resistant rate to Lfx in group D was 45.8％ (33/72),which was higher than that in group A (2/30,6.7％),group B (6/28,21.4％) and group C (8/53,15.1％) (x2 =14.413,5.047 and 13.087,P ＜0.05).The occurrence of pre-extensively drug resistance (Pre-XDR) in group D was 34.7％ (25/72),which was higher than that in group A (3/30,10.0％) and group C (9/53,17.0％) (x2 =6.499 and 4.852,P ＜ 0.05).Among 157 MDR-PTB patients who received standard anti-tuberculosis treatment for one year,the negative conversion rate of mycobacterium tuberculosis in sputum culture was 87.3％ (137/157).The negative conversion rate in group D was lower than that in other groups,but the difference was not of statistical significance (x2 =1.899,P ＞ 0.05).Conclusions The efficacies of second-line anti-tuberculosis drugs vary among MDR-TB patients resistant to different firstline anti-tuberculosis drugs.The sensitivity tests results of the first-line drugs may serve as reference for MDR chemotherapy regimen in lack of test results of second-line drugs.