Abstract: Achyranthes bidentata Blume is widely used as a traditional Chinese medicine with the effects of nourishing the liver and kidneys and strengthening muscles and bones. In this work, a rapid and simple strategy was developed for characterizing phytoecdysteroids by ultra-high-performance liquid chromatography coupled with liner ion trap-Orbitrap mass spectrometry using electrospray ionization in the negative mode. As a result, 47 phytoecdysteroids were unambiguously or tentatively characterized. Among them, seven known compounds were identified according to the reference standards along with molecular formula, retention time and fragmentation patterns, while others were mostly potential new compounds. Through targeted isolation, the structures of three new compounds were determined by NMR spectra, which were consistent with LC-MS characterization. The present study provides an efficient method to deeply characterize phytoecdysteroids.