Aiming at the interface friction traits of pile-soil, arranges the geogrid in the compacted soil cement pile - soil interface to enhance the interaction between rammed cement-soil pile and soil. Applies 3D numerical software to simulate direct shear test and static load test, analyzes the contact surface stress, deformation and intensity variation for the geogrid composite cement-soil pile and soil. The results show that the interface peak frictional resistance will increase, and the frictional resistance curve declines slowly when reaching the peak value; In the static load test, with geogrid around the pile, the corresponding subgrade settlement is smaller than that without geogrid, and the pile axial deformation is much smaller.