Abstract: With the use of vibration field along the screw axial direction, the melting and plasticizing process of vibration induced single-screw extruder varied periodically and the change of polymer viscoelasticity was non-linear,which could not be described by the classical melting theory. The dynamic transparent barrel visualization experimental method and the static half-open barrel visualization experimental method were adopted to investigate the influence of vibration parameters on the melting and plasticizing process.Melting mechanism was analyzed, and the melting physical model was established. Mass balance equation, momentum balance equation, energy balance equation and constitutive equation of the melting process with vibration were presented. With the help of sophisticated mathematical deduction, equations of melting rate and thickness of melt film were obtained.Melting rate and thickness of melt film was related to vibration parameters and was time-dependent.Melting rate increased while thickness of melt film decreased by vibration.Calculation were in good agreement with the result of experiment.