The invention discloses a detecting method for high performance liquid chromatography-tandem mass spectrometry of PDE5 type inhibitors in drugs, healthcare products and food. Acetonitrile is used as extractant. 50 percent of acetonitrile is used as diluent. A formic acid-ammonium acetate solution-methanol-acetonitrile system is used as a flowing phase. With a flowing speed of 0.2-0.4 ml/min and a column temperature of 20-50 DEG C, liquid chromatographic column performs separation, then electrospray ionization (ESI) ion source is adopted for ionization, a positive ion mode is adopted for fully scanning a primary and a secondary mass spectrum, and whether the PDE5 type inhibitors is added in a sample can be qualitatively judged according to the secondary mass spectrum. The detecting method has simple sample pretreatment, high accuracy, good specificity, high detection flexibility and short analysis period, can accomplish qualitative analysis of 11 PDE5 type inhibitors through one experiment, is suitable for microscale analysis of the PDE5 type inhibitors and can be used as a verification and arbitration method for supervision inspection.