Three seismic waves illustrated in this paper refer to reflected compressional wave, refracted compressional wave and Rayleigh wave. The horizontal correlations means correlation of properties between wave fields of the three waves and correlation between seismic velocities obtained from their inversion results. The aim of the correlation is to determine the horizons as well as the strata that form the three waves in seismic sections and to provide theoretical basis for comprehensive inversion by means of cross association of the three waves. This paper is an important part of method and theory which can be used in simutaneous multitype wave exploration. It recounts the classification method and naming method based on the relation between velocity values in strata and between horizons in the section with the purpose of adopting this new forward and inversion technique for multitype wave exploraton. Finally, the paper discusses the horizontal correlation in the light of relationship between the wave field characteristics and the velocity values.