OBJECTIVE： To establish the method for content determination of 6 kinds of triterpene acids such as haw acid， corosolic acid， betula acid， betulonic acid， oleanolic acid and ursolic acid in Tibetan medicine Rubus biflorus. METHODS： Pre-column devrivatization HPLC-FLD-APCI/MS method was adopted. 2-（7H-dibenzo[a，g]carbazol-7-yl） ethyl-4-methylbenzene- sulfonate was used as the pre-column derivatization reagent．Hypersil C18 column was used with the mobile phase consisted of 5％ acetonitrile water solution-acetonitrile （gradient elution） at the flow rate of 1.0 mL/min. The excitation wavelength of fluorescence was 300 nm and the emission wavelength was 395 nm. The column temperature was 35 ℃， and sample size was 10 μL. Under atmospheric-pressure chemical ionization （APCI） source in positive-ion mode， pressure was 60 psi， the drying gas flow rate was 9 L/min， the dry gas temperature was 350 ℃， the gasification temperature was 450 ℃， and the capillary voltage was 3 500 V. RESULTS： The linear range of haw acid，corosolic acid，betula acid，betulonic acid，oleanolic acid and ursolic acid were 0.025-6.4 μg/mL（r≥0.999 6）. The quantitative limits were 5.11， 4.78， 4.42， 4.22， 4.29， 4.51 ng/mL； and detection limits were 1.42， 1.27， 1.30， 1.28， 1.16， 1.22 ng/mL， respectively. RSD of precision test was less than 5％， stability and repeatability tests were all less than 2％（no betulonic acid detected）. The recovery rates were 97.90％-100.55％（RSD＝1.00％，n＝6）， 97.95％-102.95％（RSD＝1.74％，n＝6）， 96.00％-101.20％（RSD＝2.00％，n＝6）， 93.25％-104.20％（RSD＝4.25％，n＝6）， 92.20％-103.30％（RSD＝3.58％，n＝6）， 97.80％-103.50％（RSD＝2.03％，n＝6）， respectively. CONCLUSIONS： The method is accurate， reliable and exclusive， and can be used for simultaneous determination of 6 kinds of triterpene acids in Tibetan medicine R. biflorus.