Abstract: This paper deals with the problems of quantitative predication of location of interbed shear zone in perpenticular direction findings in theory. In the beginning, the mechanism is studied further and new classification is proposed; The concept of scale is introduced; The exteral and interal factors effecting on the location of shear zoner and how to take them into consideration are discussed. Then, two models are developed to quantitatively describe the charactertics of alternate hard-soft layersand to predict the position of shear zones within different elements. Finally, a systematic methodiology on the quantitative prediction of loaction of shear zones in the perpendicular direction is proposed. It was used in predicition of shear zones in Gao BaZhuo dam site.