Abstract: The evenly crushed Dendrobium nobile Lindl. Sample (1 g) was taken, and placed in a 50 mL-polytetrafluoroethylene centrifuge tube. 5 mL of 0.1 mol·L⁻¹ hydrochloric acid solution was added, and the mixture was vortexed for 2 min to immerse fully. 15 mL of ethanol was added, and the mixture was vortexed for 1 min,and sonicated for 30 min. After cooling to room temperature, 6 g of anhydrous magnesium sulfate and 1.5 g of anhydrous sodium acetate were added. The mixture was shaken for 3 min, cooled in an ice bath for 5 min, and centrifuged at a rotational speed of 8 000 r·min⁻¹ for 5 min. 1 mL of supernatant was taken and diluted to 25 mL with ethanol, and dendrobine and erianin were determined by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Kinetex F5 chromatographic column was used as the stationary phase and the mixed solution composed of ethanol and 0.1% (volume fraction) formic acid solution at different volume ratios was used as mobile phase for gradient elution．Electrospray ion (ESI) source was used for mass spectrometry. The targets were analyzed by multiple reaction monitoring (MRM) mode in positive (ESI⁺) scanning mode. As shown by the results, linear relationships between the corresponding peak areas and mass concentrations of dendrobine and erianin were found in definite ranges, with detection limits (3S/N) of 0.02, 0.003 mg·kg⁻¹, respectively. Test for recovery was made by the standard addition method, giving results in the range of 93.6%-97.1%, with RSDs (n=6) of the determined values less than 3.0%. This method was used to determine the dendrobine and erianin in different cultivation methods, different years, and different parts of Dendrobium nobile Lindl., and there were differences among them.