By analysis of mass spectra of sibutramine and an unknown compound in a health supplement for anti-obesity,this paper proposed the mass fragmentation pathways of sibutramine and the unknown compound,and deduced the structure of the unknown compound by piecing together fragments of the compound detected on a high-resolution mass spectrometry.The compound of the structure was synthesized and its structure was elucidated by analysis of elements,infrared spectrometry,mass spectrometry and nuclear magnetic resonance.With the synthesized compound as the reference substance,a verification examination of the sample was performed by HPLC-MS/MS.The results indicated that a new sibutramine analogue was adulterated in the sample.The study provided an effective strategy in detection and verification on analogues of synthesized drugs adulterated in health supplements.