To systematically identify the related substances in the original materials of breviscapine injection, 18 batches of samples collected from different pharmaceutical companies, its ethanol extract and breviscapine mother liquor concentrate were analyzed by high performance liquid chromatography (HPLC), and their structures were identified by ultra performance liquid chromatography and quadruple/time-of-flight mass spectrometry (UPLC-QTOF-MS). Under the selected chromatographic conditions, scutellarin and related substances have good resolution and 13 related substances were observed. Based on the molecular weight and fragmentation patterns obtained by UPLC-QTOF-MS as well as reference substances, their structures were elucidated as 6-hydroxyapigenin-6-O-glucosyl-7-O-glucuronide (1), 5,7,8,3',4',5'-hexahydroxyflavone-7-O-glucuronide (2), 5,6,7,3',4'-pentahydroxyflavone-7-O-glucuronide(3)and its isomer (4), patuletin-3-O-glucuronide (5), methoxylscutellarin (6), apigenin 7-O-glucuronide (7), isorhamnetin 7-O-glucuronide (8), diosmetin 7-O-glucuronide (9), scutellarein (10), scutellarin methyl ester (11), scutellarin ethyl ester (12), and apigenin (13). This study has clarified related substances in the original materials of breviscapine injection, providing references for the improvement of quality control for breviscapine drug material and its preparations.