A high performance liquid chromatography-mass spectrometric（HPLC-MS/MS） method was proposed for the determination of 6 anti-obesity chemical drugs（sibutramine，N-di-desmethyl sibutramine，fenfluramine，phenolphthalein，rimonabant，orlistat）added illegally into health foods.The conditions of extraction procedures and the parameters of HPLC-MS/MS were optimized.The drugs were extracted with methanol，and separated on a C8 chromatographic column using a mixture of acetonitrile and 10 mmol/L ammonium acetate solution as mobile phase with gradient elution.The detection of 6 targeted compounds was performed by positive-ion electrospray ionization mass spectrometry（ESI MS） under multiple reaction monitoring（MRM） mode.Good linearities for 6 compounds were obtained in the range of 0.001-0.5 mg/L with correlation coefficients greater than 0.999.The spiked recoveries were in the range of 81%- 100%with RSDs of 4.8%-6.9%.The detection limits of these drugs were up to 0.5 μg?L-1.The results indicated that this method was simple，rapid and accurate，and was successfully applied in the examination of examine chemical drugs illegally added in the dietary supplement.