Abstract: Experimental and numerical studies on pile-soil interaction mechanism of passive laterally loaded free-head short piles in sand were presented.Physical model tests were performed using loose,medium and dense sand to investigate the relationship between retaining wall loading and displacement,the response low of displacement of pile top to the displacement of retaining wall as well as the load transfer mechanism for piles and soil.A two-dimensional discrete element method(Particle Flow Code in Two Dimensions) was used to carry out the simulation of the relationship between the stress and the displacement of soil and piles owing to the pile-soil interaction behavior during the loading procedure.Experimental results were compared with those from numerical analysis.The study would be helpful to deeply reveal the pile-soil interaction law and raise the design level of passive laterally loaded piles.