The invention discloses an airway connecting mechanism for an air impermeability detecting device. The airway connecting mechanism comprises a supporting base for fixing a workpiece to be detected anda quick-plugging connector located on a moving path of the supporting base, wherein a seal pad is arranged on the supporting base, a cavity is formed between the seal pad and the workpiece to be detected, and the face, in butt joint with the quick-plugging connector, of the supporting base is provided with an air nozzle communicated with the cavity, so that the cavity is communicated with the quick-plugging connector when the air nozzle is inserted into the quick-plugging connector. The airway connecting mechanism for the air impermeability detecting device in the scheme is provided with thequick-plugging connector which can be communicated with an air source and the cavity formed between a seal structure and the seal pad, accordingly facilitates air impermeability detection of the sealing structure and is simple in structure and stable in operation.