Objective A high-performance liquid chromatography electrosp ray/mass spectrometry ( HPLC /ESI2MS) method was developed to detectN-di-desmethylsibutramine in slimming health food p roducts. Method The separation was comp leted on a RP-C₁₈ column ( 416 mm ×250 mm, 5 μm) with 0125% acetic acid aqueous solution containing 20 mmmol/L ammonium acetate asmobile phase. Elution run at a flow rate of 1 ml/min and UV detection was performed at 223 nm. Results Good linearity was shown between the peak area and the concentration of N-di-desmethylsibutramine standards, in a range of 010121120 mg/ml. Conclusion The correlation coefficient of the calibration curves was better than 019997 ( n = 6). The limit of detection (LOD) was 0195μg/ml (S /N = 3). Themethod was sensitive, p recise and highly rep roducible.