OBJECTIVE:To establish an HPLC method for the determination of the content of ethambutol hydrochloride in ethambutol hydrochloride-pyrazinamide-rifampicin-isoniazid tabletsⅡ.METHODS:The sample was separated on Alltima CN column.The mobile phase was acetonitrile-triethylamine(50:50)water solution at a flow rate of 1.0 mL?min~(-1).The diluent agent was Na_2HPO_4 solution.The detective wavelength was set at 200 nm;the column temperature was maintained at room temperature and the sample size was 20?L.RESULTS:The linear range of ethambutol hydrochloride was 100.2～601.2?g?mL~(-1)(r=0.999 98)and its average recovery was 99.8%(RSD=0.374%).CONCLUSIONS:The method is simple,accurate and reproducible,and it can be used for the content determination of ethambutol hydrochloride in this tablet.