Non-destructive and non-contact characterization of adhesion by surface acoustic waves (SAW) is an important goal for thin film coating. In this work, SAW are generated by a Nd: YAG laser on an aluminum sample covered by a PVC film of a uniform thickness. The normal displacement is detected at aluminum surface by an interferometer. The influence of the adhesion levels is observed on acoustic signals and a model using finite element method compares theoretical and experimental results. A Matlab code is also developed to plot the dispersion curves according to the transfer-matrix method. It allows to characterize quality of adhesion.