The study of pile foundations in liquefiable soil subjected to dynamic loading is a very complex and coupled process. A finite-difference-based computer program FLAC3D is used to model the dynamic response single pile and obtain the deflection and bending moment behavior along with the depth of the pile, under seismic loading conditions in liquefiable soil. The present study has used a nonlinear constitutive model for soil liquefaction and soil-pile interaction simulation.Also, liquefaction analysis has been performed based on effective stress built-in constitutive Finn model. The main objective of this study is to evaluate the influence of the pile diameter, groundwater condition, and peak ground acceleration (PGA) on the response of laterally loaded single piles embedded in homogeneous soil. The analysis was carried out by considering free-headed flexible piles. The numerical model was validated based on a dynamic centrifuge test performed at Rensselaer Polytechnic Institute, Nework. The calculated Lateral deflection, bending moment, and shear force for piles with different diameters, and groundwater conditions for input scaled Kobe-Earthquake. In this study, the result shows that the pile head x-displacement history, lateral pile x-displacement, distribution of bending moment, and distribution of shear force along the pile length were influenced by pile diameter, groundwater condition, and peak ground acceleration. The analysis indicated that the maximum pile head lateral displacement, the maximum pile bending moment, and the maximum shear force increase when the pile diameter increases for a given peak ground acceleration value. This was due to the increase in base shear and decrease in passive resistance. The maximum bending moment and shear force values were recorded at the pile bottom.In fully submerged condition of a soil all pile responses has been decreased as compared to fully dry soilcondition. Keywords: Dynamic Analysis, Fluid-Mechanical Interaction, FLAC3D, Liquefaction, Finn