The invention discloses a method for measuring content of citric acid in ambroxol hydrochloride solution used for inhalation. The method comprises the following steps that: (1) preparing standard reference substance solution; (2) preparing sample solution; (3) independently measuring the standard reference substance solution and the sample solution of different concentrations by a high performanceliquid chromatograph, and independently recording the concentration and the corresponding peak area of the standard reference substance solution; and (4) utilizing an external standard method to solve the content of the corresponding citric acid from the peak area of the sample solution. In (3), a mobile phase A is phosphoric acid solution of which the volume ratio is 1%, a mobile phase B is methyl alcohol used for carrying out gradient elution, a column temperature is 30DEG C, flow velocity is 1.0mL/min, detection wavelength is 214nm, a sample introduction amount I 10[Mu]L, a chromatographiccolumn adopts a C18 column, and the specification of the chromatographic column is that an internal diameter is 4.6mm, column height is 150mm and the aperture of filler is 5um.