The herb Fissistigma oldhamii var. longistipitatum has been used for a long time in Asian folk medicine in the treatment of several diseases, including rheumatoid arthritis and other inflammatory conditions. Researchers in China and elsewhere have analyzed and characterized its chemical content. In this study, a UHPLC-Q-TOF-MS/MS method, run in both positive and negative modes, was used to identify the main chemical compounds in dichloromethane extracts of this F. oldhamii variant. A total of 64 compounds, including 44 alkaloids and 20 flavonoids, were rapidly identified or tentatively characterized by comparing the molecular ion peaks and MS2 mass spectrometry fragment ions, combined with the mass spectrometry information of reference substances, appropriate fragmentation ions and related literatures. For the first time, the developed UHPLC-Q-TOF-MS/MS analysis method allows for the determination of 64 compounds from extracts of the F. oldhamii variant. The method presented here produced results that will be useful in further studies of this herb.