Abstract: In this paper,both the longitudinal direction vibration state of medium particle in the central axis and the oblique direction vibration state of medium particle around the central axis were analyzed during the longitudinal wave propagation process of solid dielectric.The position of the transverse wave that followed the longitudinal wave was quantitatively calculated and experimentally verified.The results proved that the intensity of transverse waves produced in second medium was much less than the the intensity of longitudinal waves,when the longitudinal transducer entered on the solid interface vertically.