Abstract: Based on an example of a variational section bored pile,numerical simulation of its load transfer performance of that variational section and equal section single-pile sustain top-pile load under same soil conditions are carried with 3D FEM.The effect of pile styles are discussed,by introducing relative soil friction R_τ for explaining the exertion degree of soil friction.The results indicated that if R_τ=1.0,soil friction brings into full play;if R_τ>1.0,the soil friction represents consolidation phenomena;if R_τ<1.0,it indicates that soil friction represents intenerating phenomena.