Abstract: A method for the rapid quantification of triterpenoids in Ganoderma lucidum by ultraviolet （UV） spectrometry is established. A triterpenoid standard dissolved in saturated NaHCO<SUB<3</SUB< has a maximum absorbance at 257 nm by UV spectrometry. The concentration of the standard is correlated very well to its optical density at 257 nm in the range of 0～(200.0 μg·mL<sup<-1</sup<) with a relativity coefficient of （0.999 88.） The supernatant NaHCO<SUB<3</SUB< solution was collected and measured in the intermediate stage of triterpenoids extraction by a UV spectrometer. The content of triterpenoids in Ganoderma lucidum material was then counted according to the standard curve. The above method for the quantification was proved to have the advantages of easy operation, high accuracy, having less error and fine repetition, and it shound be helpful for monitoring the quality of Ganoderma lucidum material and related products.