To establish a method for analyzing Borneol and its metabolites in rabbit serum, the sample was separated and analyzed by SPE/HPLC - APCI MSn. Metabolites of Borneol in rabbit serum were identified by mass spectrometry. They are m/z 227. 1 , 340. 2 and 114. 0. The metabolism of Borneol was discussed, and the conclusion can be applied to the study on similar structural substances.