A indirect method for the determination of tetradecyl pyridyl bromide (TPB) was established (TPB) by flame atomic absorption spectrometry (FAAS). TPB was combined with cadmium tetrathocyanate to make neutral ion association compounds, which are extracted into xylene. The concentration of TPB can be indirectly determined by the absorption of cadmium in xylene layer with flame atomic absorption spectrometry. The linear range of TPB is 0.03-0.80 mg/L. The sensitivity is 0.0212 mg/L x 1%. When the method was applied to the analysis of waste water, the recovery is from 98% to 104% and the RSD is less than 9.16%.