Abstract: By using the Marc program,the spatial axisymmetrical finite element model was established;and with the Visual-Fortran platform,the function of the large common finite element MARC program was secondly developed.Two subroutines were written including the SUBROUTINE UINSTR for soil initial stress analysis and the SUBROUTINE UFRIC for dynamic contact analysis.With the model,this paper analyses the modulus of the injecting cement and the influence of thickness on the bearing performance of a large diameter bored pile.The following results are obtained:(1)the modulus of the injecting cement around the pile has no influence on the bearing performance of the pile;(2)the rational thinness of the injecting cement around the pile is 18～25 cm;(3)by injecting cement around and under the pile,the bearing performance of pile are improved by about 40%,20% and 14%,when the corresponding length of the pile is 10 m,30 m and 50 m.The simulation results agree with the actual data.The model is proved to be appropriate.