Abstract: Rubusoside is a major sweet component in Rubus suavissimus S . Lee(sweet tea), which is a special product of Guangxi Province, China. A liquid chromatography-electrospray ionization mass spectrometry(LC- MS/MS) method was developed for the determination of Rubusoside in sweet tea．After pretreatment procedure，sample was separated on a ACQUITY UPLC@BEH C₁₈(2.1×100 mm i.d.;1.7 μm) column with a mobile phase consisting of V(acetonitrile(0.1％formic acid)):V(distilled water(0.1％formic acid)＝20:80 and injection volume of 5 μL at a flow-rate of 1.5 mL min^－1 and the column temperature was 35 ℃. Detection was performed by Waters mass spectrometer using multiple reaction monitoring(MRM) mode via electro spray ionization(ESI) source and selecting m/z 643-319 as detecting ion. A good linear calibration is obtained for 0.1-10 mg L^－1 with a correlation coefficient of 0.999 3. The recoveries are in the range of 95.3％-97.7％. The limit of Determination is 0.04 mg L^－1, and the limit of Quantification is 0.1 mg L^－1. The proposed method is simple, sensitive and reproducible enough to be used for the determination of Rubusoside in Rubus suavissimus S . Lee．