Abstract: A lot of mixed backfill foundation exist in Beijing city mostly because of the excavation of sand. The composition of this kind of foundation is complex, including structural garbage, industrial garbage and living garbage. The optimal ground treatment methods must be adopted in this kind of foundation for its difference of thickness, negative friction, remarkable difference of uniformity, low bearing capacity, high compressibility, high indeterminacy and nothing of regularity. This kind of foundation is usefull in the buildings only after ground treatment. Taking Beijing Pearl River Luxury Apartment as an example, the component type foundation treatment of Beijing urban mixed fill is dissertated. The effect of the treatment is analyzed by the test and the data of settlement in high-rise building. The elementary conclusion is educed.