Ram-compaction pile can tamp bearing soil layers to densify the stratum in water. The bearing capacity of composite foundation can be greatly increased and engineering investment can be reduced by use of compressibility of flyash cushion and high bearing capacity of ram-compaction pile. The composite foundation, made up of ram-compaction rigid piles and fly-ash cushion, is introduced with the application of a high-rise building in Luoyang, Henan.