A simple and reliable ultra performance liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry method (UPLC-TOF-MS) was developed and validated for the simultaneous determination of the major bioactive constituents in Acanthopanax senticosus and its extract. The separation of five compounds was performed on a UPLC™ HSS T3 column (100 mm × 2.1 mm, 1.7 μm) with gradient elution using a mobile phase consisting of 0.1% aqueous formic acid and acetonitrile containing 0.1% formic acid. All targeted compounds (syringin, chlorogenid acid, caffeic acid, eleutheroside E and isofraxidin) were baseline separated within 5.3 min in samples, which represented an approximate six-fold reduction in the analysis time in comparison to published HPLC method. Quantitation was carried out working in the V mode using the narrow widow extracted ion chromatograms (nwXICs) of each compound (extracted using a 20 mDa window). Furthermore, all calibration curves showed good linearity (r > 0.999) within the test ranges. The precision was evaluated by intra- and inter-day tests, which revealed relative standard deviation (RSD) values of less than 3.88%. The recoveries for the quantified compounds were between 96.3% and 103.7%, with RSD values below 2.89%. According to the literature, this study represents the first investigation of the simultaneous analysis of multiple components and the method can be applied to determine the amounts of the major compounds in Acanthopanax senticosus and its extract by UPLC-TOF-MS.