The aim of this paper is to systematically identify the characteristics regarding the stress/deformation of pile foundations with super-structure subjected to lateral load on multiple layers ground by elastic analysis. The characteristics of stress/deformation of piles could be treated 'as equivalent to single layer ground. The values of equivalent ground factor β_o for pile top bending moment M_o, β_m, for maximum bending moment along pile length M_m and β_a for pile top shear force Q_o were strongly related to the non-dimensional depth of the upper layer. The influence of structural rigidity and the difference between center and corner piles were able to be evaluated by non-dimensional restraint factor ω.
