Objective To establish an analysis method for simultaneous determination of 15 kinds of pyrrolizidine alkaloids (PAs) in tea by ultra-high performance liquid chromatography-high resolution mass spectrometry. Methods Formic acid aqueous solution and methanol were used as extraction solvent. After the ultrasonic extraction and MCX solid phase extraction purification, the analytes were separated with HSS T3 chromatographic column (50 mm×2.1 mm,1.7 μm) using 4.0 mmol/L ammonium formate solution(0.1% formic acidinclusive) and methanol as mobile phase for gradient elution. Finally, the eluents were determined by full scan/data independent acquisition (Full MS/DIA) of high resolution mass spectrometry in positive mode. Results Depending on the comprehensive data, the characteristic structural fragment ions of 3 kinds of PAs were screened out. Good linearities in the range of 0.5-200 μg/L were observed for 15 kinds of PAs (R²＞0.99), the limits of detection (LODs) and the limits of quantification (LOQs) were 0.35-4.69 μg/kg and 1.18-11.17 μg/kg, respectively. In this study, 20 commercial tea samples were analyzed using this method, and Jacobine was detected in 1 camomile tea sample, all the other measured values were lower than the LODs in the method. Conclusion This method has high sensitivity and stability, can meet the simultaneous detection requirements of 15 kinds of PAs in tea.