Aurantio-obtusin (AO) is a major anthraquinone compound isolated from Cassiae Semen or Duhaldea nervosa, which possesses diverse pharmacological effects. Previous studies have shown that it has a good effect on lowering blood lipids and treating various diseases. A few studies have also reported about its metabolites. A rapid and reliable method using ultra-high-performance liquid chromatography-Q-Exactive Orbitrap mass spectrometry and multiple data-processing technologies was established to investigate the metabolites of AO in the plasma and various tissues of rats, including the heart, liver, spleen, lung, kidneys, and brain. Finally, a total of 36 metabolites were identified in the plasma of rats, which could be very beneficial for understanding the effective form of AO metabolites leading to new drug discovery. The result demonstrated that this strategy, especially parallel reaction monitoring, has shown a wide range of applications in the identification of metabolites.