Objective To establish a method for determination R ifamycin sodium in the cerebrospinal fluid of patients with tuberculous meningitis by HPLC-MS/MS.Methods Column was XTerraMS C18(4.6 mm×100.0 mm,3.5 μm).Mobile phase was Ammonium acetate (0.01 mol/L)-Methanol(10:90).Flow rate was 0.4 ml/min.Multiple reaction monitoring (MR M)was used by HPLC.Results The linear ranges of 0.4-4.0 μg/ml(r=0.9997)was better;Detection limit was 100 ng/ml. Conclusion The method is simple,rapid,accurate,and it can be used for therapeutic drug monitoring.