The present study was designed to develop and validate a rapid, sensitive, and reliable ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous determination of five major active constituents in the traditional Chinese medicinal preparation Xingxiong injection (XXI) in rat plasma, including quercetin 3- O-rutinoside (QCR), kaempferol 3- O-rutinoside (KFR), isorhamnetin 3- O-rutinoside (ISR), bilobalide (BB), and ligustrazine (LGT). The plasma samples were pretreated by protein precipitation with acetonitrile. The chromatographic separation was achieved on a Waters Symmetry C 18 analytical column (2.1 mm × 100 mm, 3.5 μm) with a mobile phase of 0.1% aqueous formic acid (A)–acetonitrile (B). Quantitation of the five bioactive constituents was achieved. Naringin was used as the internal standard (IS). All the calibration curves showed good linearity ( r > 0.996) over the concentration range, with the lowest limit of quantification (LLOQ) between 2–18 ng·mL −1. The intra- and inter-day accuracy and precision of the analytes were both within acceptable limits. Moreover, satisfactory extraction recoveries (90.92%–104.03%) were obtained by protein precipitation. The validated method was successfully applied to a pharmacokinetic study of XXI in rats after intravenous administration at three doses. The pharmacokinetic parameters of the five compounds varied in a dose-dependent manner within the tested dosage range. The present study was the first report of pharmacokinetic study for XXI.