Abstract: Xanthii Fructus is the dried mature fruit with involucre of Xanthium sibiricum Patr. It has multiple pharmacological effects, including anti-inflammatory and analgesic, antibacterial, antiallergic, antitumor activities. Compared with the raw herb, stir-fried Xanthii Fructus has lower toxicity while retaining equivalent pharmacological efficacy. In traditional Chinese medicine, it is primarily used for treating symptoms such as allergic rhinitis. Our preliminary studies have indicated that the ethanol extract of stir-fried Xanthii Fructus demonstrates positive therapeutic effects on rats with rheumatoid arthritis, which can effectively reduce the levels of inflammatory mediators such as TNF-α and IL-1β. However, the precise chemical constituents responsible for its therapeutic effects remain to be elucidated. In this study, a method of ultra-performance liquid chromatography coupled with quadrupole-electrostatic field Orbitrap high-resolution mass spectrometry (UPLC-Q-Orbitrap MS) was established for the analysis of stir-fried Xanthii Fructus. Firstly, the components of stir-fried Xanthii Fructus were extracted by the heated reflux extraction method using 75% ethanol as the extraction solvent, with the extraction process repeated three times. Subsequently, the ethanol extract was separated on a Waters Acquity UPLC HSS T3 column (100 mm×2.1 mm, 1.8 μm). The mobile phase consisted 0.1% formic acid aqueous solution (A) and methanol (B) at a flow rate of 0.3 mL/min, with gradient elution applied. The electrospray ionization (ESI) source was utilized, which facilitated the execution of full scanning and secondary mass spectrometry scanning under both positive and negative ion modes, respectively. Finally, the acquired data were processed for peak extraction, peak alignment and deconvolution using Progenesis QI 3.0 software for comparison with reference substance databases and other theoretical databases, such as ChemSpider, PubChem, PubMed and Web of Science. A total of 26 chemical components were identified, including 15 phenylpropanoids, 4 organic acids, 2 flavones, 2 sesquiterpenes, 2 glycosides and 1 other component. Among them, phenylpropanoids and organic acids such as chlorogenic acid, caffeic acid, cynarin, ferulaldehyde, isochlorogenic acid A, isochlorogenic acid B, and isochlorogenic acid C were more abundant and response in the mass spectra. The mass spectrometry fragmentation pathways of representative compounds in each class were also analyzed. This study provides a basis for the further exploration of the pharmacological effects and in vivo metabolic processes of stir-fried Xanthii Fructus.