To discuss the behavior of piles in non-homogeneous soil（the soil shear modulus profile follows power law with depth）under combined loading of vertical force Vand torsion T

the control equation of the pile shaft was first set up based on the pile shear displacement method and shaft load transferring function

in which the non-zero shear modulus at the ground surface and the non-coordination deformation along the pile-soil interface and various loading sequence were considered as well.Then

force and displacement boundary conditions were introduced to deduce the analytical solutions for the internal force and deformation of the pile shaft under various bearing stages of subsoil

from which the bearing capacity of the pile shaft were calculated and the failure envelops were plotted under various loading sequence.Parameter analysis shows that

for V-Tcombined loaded piles

the bearing capacity will increase with the increasing of aspect ratio L/D

whereas decrease with the increasing of the constant ratio between the subsoil shear modulus and the ultimate friction resistance（n）

and the stiffness ratio（λ）between pile shaft and subsoil.Increasing the torsion at the top of pile will result in a decreasing vertical bearing capacity with a final zero value.Besides

the failure envelop under T→Vloading sequence remains inside of that under V→Tloading sequence.