Abstract: The sample was extracted ultrasonically with 15 mL of 40% (φ) methanol solution for 20 min. Ultimate UPLC XB-C18 column (150 mm×2.1 mm, 1.8 μm) was used as stationary phase, and a mixture of acetonitrile and water (45+55) was used as mobile phase. Negative electrospray ionization was used in detection. Chloramphenicol was used as internal standard. Linearity ranges of ganoderic acid A and ganoderic acid B were found between 0.051 3-0.513 mg·L-1 and 0.020 8-0.125 mg·L-1, with detection limits (3S/N) of 0.15, 0.062 mg·L-1 respectively. The proposed method was applied to the analysis of substantial tea samples, giving values of recovery and RSD′s (n=9) in the ranges of 96.0%-104% and 1.1%-2.8% respectively.