The pier foundations for transmission towers, high-rise buildings and bridges are constructed near steep slopes and have to be designed mainly to resist large lateral loads, such as violent winds, earthquakes and high-speed vehicles. The behavior of a pier foundation subjected to the lateral loads looks like that of a short pile very much, because the failure of both a pier foundation and a short pile seem to depend on the rotation developing passive resistance on slope side above the rotation point unlike behavior of long pile. Short piles near slope are supposed to have a significant effect upon the pile response to lateral loading, however, relatively little information is available to guide designers in attempts to quantify this effect. This paper describes the results of several numerical studies performed with a 3D finite element analysis based on the model tests for a laterally loaded short pile, with large-diameter pile, installed near slopes. Authors carried out a series of model tests and FE analysis of the laterally loaded short pile groups installed near the slope. From these results, we found quantitatively that the lateral resistance of pile depends on several factors, such as loading heights from the ground surface. In the 3D FEM, the failure criterion and the plastic potential are based on the Mohr-Coulomb and the Drucker-Prager equations, respectively. The pile was assumed as linearly elastic material and the soil was modeled as an elasto-perfectly plastic one with non-associated plasticity.