A method was developed for the screening and confirmation of 28 illegally added phosphodiestrase-5 inhibitors（PDE-5） including sildenafil，tadalafil，vardenafil and analogues in health foods by liquid chromatography-ion trap-time of flight tandem mass spectrometry（LC-MS-IT-TOF）．The accurate mass and multiple-stage mass spectrometry databases of 28 compounds were established.The analytes in samples were extracted with methanol and separated on a C18 column（150 mm×4.6 mm,3.5 μm） by gradient elution using acetonitrile-0.1% acetic acid as mobile phase.The results showed that the limits of detection（LOD，S/N≥3） were in the range of 0.2-7.0 μg/L.The limits of quantitation（LOQ，S/N≥10） were in the ranges of 0.04-1.18 mg/kg for capsule and 0.007-0.235 mg/L for oral solution,respectively．The method validation was carried out by LOQ levels，and the recoveries were in the range of 31.0%-114.0% with relative standard deviations（RSDs） of 25%-149%．The screening of analytes was performed by precision mass matching and library searching.The retention time,isotopic abundance and multiple-stage ion mass spectra were employed for the confirmation.This method is simple,rapid,credible and sensitive,and could be applied in the simultaneous screening and identification for illegally added PDE-5 and analogues in health foods.Moreover,the ion fragmentation patterns of these drugs could be exploited to predict the chemical formulas and structures of the unknown derivatives and structural analogs of phosphodiestrase-5 inhibitors.