Abstract: The study was aimed to identify the related substances of vortioxetine hydrobromide by hyphenated techniques. The separation of the six related substances was performed on a Phenomenex Luna Phenyl- Hexyl column (150 mm×4.6 mm, 3 μm) by linear gradient elution of acetonitrile and ammonium formate solution. Electrospray and atmospheric pressure chemical ionization were interfaced respectively with high resolution Q-TOF/MS for the determination of the accurate mass and elemental composition of the parent ions of the related substances, and triple quadrupole tandem mass was employed for the product mass spectra determination. The structures of the related substances were identified through elucidation of the fragment ions. Vortioxetine hydrobromide and its related substances were adequately separated under the established HPLC conditions. Six major related substances were detected and identified for the first time. The data provides a reference for optimization of the synthetic process and quality assurance of vortioxetine hydrobromide.