Abstract: A method of LC-MS/MS for the determination of residual amount of tebufenozide in orange was proposed. The sample was extracted twice with a mixture solution of 0.1% (φ) acetic acid-acetonitrile, and the extracts were made up to 25 mL. An aliquot of 8.0 mL was taken and purified with PSA and ODS. A portion (5.00 mL) of the purified solution was evaporated to near-dryness at 60 ℃ by N2-blowing, and the residue was dissolved, made up to 1.0 with 0.1% (φ) acetic acid-acetonitrile, and used for LC-MS/MS analysis. ACQUITY UPLC BEH C18 column was used as stationary phase, and the mixture of acetonitrile and 0.1% (φ) acetic acid solution mixed in different ratio was used as mobile phase in gradient elution. ESI+ as well as multi-reactions monitor was adopted in MS/MS. Value of detection limit (10S/N) of the method found was 0.005 mg·kg-1. On the base of blank orange sample, test for recovery was made by standard addition method; values of average recovery found were in the range of 77.1%-90.1% with RSD′s (n=5) less than 13%.