Objective To study the clinical effect of drug administration under fiberoptic bronchoscope in the treatment of multi drug resistant (mdr) cavitary pulmonary tuberculosis. Methods 74 patients with cavitary pulmonary tuberculosis(who were resistant to INH and RFP at the same time and sensitive to other drugs in other drug sensitivity tests) were selected as the study subjects. 38 of them were set up as the treatment group. On the basis of the treatment with traditional antituberculosis drugs such as pasiazide, EMB, PZA and TH1321, they were treated with fiberoptic bronchoscopy and drug selection AMK and levofloxacin, 36 cases as control group, were treated with traditional antituberculotic drugs, such as pasiazide, EMB, PZA and TH1321. Results The total effective rate of clinical treatment in the treatment group was 94.7%, higher than 66.7% in the control group, and the difference between the two groups was statistically significant(P<0.05);there was no difference in adverse reactions between the two groups(P>0.05). Conclusion Administration of AMK and levofloxacin under fiberbronchoscope may effectively treat mdr-cavitary tuberculosis, achieve ideal clinical treatment effect, effectively improve the clinical symptoms of patients, shorten the time of sputum bacteria turning negative, focus reduction and cavitary reduction, effectively improve the quality of life of patients. The treatment safety is high, which may be applied in clinical promotion.