Abstract: Sample of tetrabenazine raw drug was dissolved with mixture of anhydrous glacial acetic acid and acetic anhydride (1+7), and the content of tetrabenazine obtained in the solution was determined by non-aqueous potentiometric titration using 0.02 mol·L-1 HClO4 standard solution as titrant. The proposed method was applied to the analysis of substantial raw drug, giving values of RSD′s (n=5) in the range of 0.32%-0.40%.