A new separation and quantification method using liquid chromatography under ultra-high-pressure in combination with tandem mass spectrometry (MS/MS) was developed for simultaneous determination of four alkaloids in Lindera aggregata. The analysis was performed on an Acquity UPLC BEH C(18) column (50mmx2.1mm, 1.7microm particle size; Waters, Milford, MA, USA) utilizing a gradient elution profile and a mobile phase consisting of (A) water containing 10mM ammonium acetate adjusted to pH 3 with acetic acid and (B) acetonitrile. An electrospray ionization (ESI)-tandem interface in the positive mode was employed prior to mass spectrometric detection. The calibration curve was linear over the range of 17.1-856ng for boldine, 42.4-2652ng for norboldine, 6.1-304ng for reticuline and 0.5-50ng for linderegatine, respectively. The average recoveries ranged from 99.2 to 101.4% with RSDs< or =2.7%. Then, four L. aggregata samples from different batches were analyzed using the established method. The results indicated that ultra-high-pressure liquid chromatography-tandem mass spectrometry provided improved chromatographic parameters resulting in significantly increased sample throughput including lower solvent consumption and lower limits of quantitation (LOQs) for most of target analytes compared to previous method employing conventional high-performance liquid chromatography (HPLC) separation. So, the established method was validated, sensitive and reliable for the determination of four alkaloids in L. aggregata.