Objective: To develop a rapid,sensitive and selective high-performance liquid chromatography coupled with mass spectrometric method(HPLC-MS) for detection oleic acid and linoleic acid.Methods: The chromatographic separation was achieved on C18 column at 35 ℃,with a mobile phase consisting of methanol-distilled water(95:5,v/v) at a flow rate of 0.4 mL/min.An in-vitro dif-fusion chamber system across isolated rat intestinal membranes was chosen as a model.A self-microemulsifying drug delivery system was used to enhance the intestinal absorption of bruces javanica oil.Results: Oleic acid and linoleic acid were separated with retention times of 10.46 ± 0.02 and 8.55 ± 0.01 min,respectively.A good linear relationship for oleic acid and linoleic acid were in the range of 0.50~50.0 ng/mL(oleic acid) and 5.06~101.2 ng/mL(linoleic acid),respectively.The mean absolute recoveries of oleic acid and linoleic acid determined in middle concentrations were 97.49±3.11 % and 105.76±3.13 % respectively.The coefficients of variation for in-ter-day and intra-day assay were less than 5 %.The absorption of oleic acid and linoleic acid in bruces javanica oil were 2.8-fold and 4.1-fold enhancement in the presence of the self-microemulsifying drug delivery system respectively,compared with brucea javanica oil alone.Conclusion: HPLC-MS method will be of great utility in routine quality control procedure for the determination of oleic acid and linoleic acid in absorption experiments.