Abstract: The model tests and PFC2D(Particle Flow Code in 2 Dimensions) numerical simulation method were applied to investigate stress and displacement of the soil around the horizontally loaded free-head short piles in sand during loading.Aimed at samples of loose,medium and dense sand,advanced digital photographic non-target method was adopted in the test to identify the digital images of the model,and to measure the change of displacement of piles and soil around them under loading.The soil pressure on lateral side of the piles,load and displacement of pile head was measured in model tests.The stress and displacement of the soil around the piles was simulated by PFC2D and compared with the results from the model tests.By analyzing the load-displacement relation of pile head,position change of piles under pile load,soil pressure distribution on the piles and its variation with load and displacement of pile head and development of stress in the soil around the piles,a deformation and failure mode of free short piles in sand under horizontal load and distribution mode of the critical earth pressure were obtained.