Abstract: Piles under uplifting load were tested with numer ical s imulation method,and the results of numerical simulation tests were compared wit h results of actual pile t ests.Using PFC^2D（Particle Flow Code in 2 Dimensions）, meso-mechanical characteristics of sand particles were simulated numerically ,and distribution and velocity of sand particles as well as uplifting displacements of pile were studied.It was found that with increase of uplifting load the sizes of affected zone of particle decr ease fro m large to small,the arrangements of particles were changed,the aff ected taper zone of particle was formed,and the correspondin g taper fractured surface can be determined.The relations between uplifting load ,disp lacement and time were simulated numerically and compared with the results of actual pile tests,and the ultimate uplifting bearing capacity was defined. The numerical sim ulation of particle flow for soi l around piles under uplifting load is just an initial study on meso-mechanical characteristics and macro-mechanic al response.