In this paper dispersion equations of Rayieigh waves are derived on thebasis of a horizontal layered liquid model. Furthermore, calculation on multi-layered media is made and curves of Rayleigh wave velocity with respect towavelength are drawn. Anomaly characterstics on the curves, which correspondto elastic subsurfaces, agree well with those on curves measured in practice,and reasonably show the mechanism of exploration in layered media by Reyleigh-wave technique. With calculations of the theoretical model, the authors alsooffer comments on the hail-wave-length interpretation method which is cur-rently used in surface wave exploration and explain the anomaly characteristicson curves recorded from solid layered media.