Abstract: HPLC was applied to the determination of 4 thiosildenafil (TSDNF) drugs added illicitly in sexual promoting health-care nutritives. The sample was extracted ultrasonically with acetonitile-H2O(1+1) solution. An aliquat of 10 μL of the extract was taken and separated on ACE C18 chromatograplic column with column temperadure at 35 ℃. The column was eluted gradiently with mobile phase of mixtures of solution (A) and (B) mixed in various ratios, in which (A) and (B) were mixtures of triethylamine solution, CH3OH and CH3CN with different volumic ratios of (60+20+20) and (8+46+46) respectively. UV detection at 230 nm was adopted. Linearity ranges of the 4 drugs were found in the same range of 1.00-100 mg·L-1. Values of detection limits (3S/N) found were same as 67 μg·kg-1. Values of recovery found by standard addition method were ranged from 92.0% to 101%, with RSD′s (n=6) all less than 1.5%. Positive samples were verified further by LC-MS/MS. The rule of MS2 fragmentation and characteristics of UV absorption spectrometry of the TSDNF′s were also studied.