Stauntonia obovatifoliola Hayata subsp. intermedia is used in China to treat rheumatic arthralgia, hernia pain, and traumatic pain. An accurate and reliable method based on high-performance liquid chromatography with diode array detection has been developed and validated for the quantitative determination of nine triterpenoid saponins in this herb. By using a Kromasil 100-5 C18 column (250 mm × 4.6 mm, 5 μm), nine analytes were separated by gradient elution over a running time of 45.0 min. All standard calibration curves demonstrated satisfactory linearity (R(2) ≥ 0.9995) within a relatively wide range. The precision was evaluated by intra- and interday tests, which revealed relative standard deviation values within the ranges of 0.20-2.83 and 0.51-2.79%, respectively. The recoveries for the nine target compounds were between 84.6 and 103% with relative standard deviation values less than 2.67%. The samples were also analyzed on a linear trap quadrupole Orbitrap Velos Pro mass spectrometer equipped with an electrospray ionization source in negative mode to confirm the quantification results. In conclusion, the present high-performance liquid chromatography with diode array detection method could serve as an accurate and reliable method for the quality evaluation of Stauntonia obovatifoliola Hayata subsp. intermedia stems.