A high performance liquid chromatography-quadrupole-time of flight mass spectrometric（HPLC-Q-TOF/MS）method with a modified QuEChERS purification was developed for the rapid screening of unkown illegal additive residues in herbal teas.The target compounds in samples were extracted with 0.5%acetic acid-acetonitrile,cleaned with NH2 sorbent and separated on a C18 column（100 mm×2.1 mm，1.7 μm）,then determined by HPLC-Q-TOF/MS.The detection limits and the quantitation limits for 8 control drugs were in the ranges of 2.0-10 μg/kg and 5.0-25 μg/kg,respectively.The average recoveries for the samples at three spiked levels ranged from 75.8%to 95.6%,with RSD（n=6）of 2.1%-6.5%.Moreover,the acquired data were compared with the library using the accurate mass,isotopic distribution,fragmentation information to screen illegal additive residues in herbal teas without reference standards.The developed method was used in the determination of 50 herbal tea samples.Results showed that paracetamol was detected in 10 samples,with content range of 4.14-2 188 mg/kg.This method is efficient,sensititive and accurate,and could meet the requirement for rapid screening of unkown illegal additive residues in herbal teas.