The characteristics of composite foundation with CFG piles are studied by finite element analyzing software,and various ground treatment methods are analyzed,such as cement-soil,pile-hat-net and pile-plank,to compare the differences of the rules of settlement and the ratio of the stress of pile and soil.It is indicated by study that the settlement of subgrade is the most but the ratio of the stress of pile and soil is the least and there will be a basin of settlement on the surface of subgrade when the subgrade is treated with cementsoil;while the settlement of subgrade is the least but the ratio of the stress of pile and soil is the most and the settlement on the surface of subgrade will be more regular when the subgrade is treated with pile-plank.