Objective To establish a rapid screening method for 85 toxic alkaloids in plasma samples using ultra-high performance liquid chromatography coupled with quadrupole/exactive high resolution mass spectrometry （UHPLC-Q/Exactive）.Methods A high resolution mass spectrometry compound database （CDB） of 85 alkaloids was established by UHPLC-Q/Exactive. Acetonitrile was used for protein precipitation as pretreatment in plasma samples. An Acquity Waters BEH C₁₈ column （100 mm×2.1 mm， 1.7 μm） was applied for gradient elution with 5 mmol/L ammonium formate （containing 0.1% formic acid） and acetonitrile as mobile phases. The screening accuracy of 85 toxic alkaloids in spiked plasma samples was compared in three data collection modes （Full mass/dd-MS²， Full mass/AIF and Full mass/DIA）.Results The screening accuracy of Full mass/DIA was the highest when plasma samples were added at three concentration levels of 5， 50 and 250 ng/mL. Combined with the CDB， a rapid screening method for 85 toxic alkaloids in plasma samples was established under the Full mass/DIA data acquisition mode. The limits of detection of more than 80% of the alkaloids in plasma samples were lower than 10 ng/mL. With this method， the target substance-yunaconitine and its possible metabolites， 3-deoxyaconitine and indaconitine were successfully screened in the 3 Wistar rat plasma samples obtained from the yunaconitine toxicokinetics experiment.Conclusion The method is fast， efficient， and suitable for the rapid screening of 85 toxic alkaloids in acute toxic alkaloid poisoned plasma samples with the absence of standard substances.