Analysis was made on design calculation, construction and detection results of CFG rock-socket pile for a foundation treatment project. The improvement on the embedding ability of spiral drilling machine made the rock-socket pile even deeper. By the analysis on the inspection data of composite foundation, the relationship and rule of pile length and settlement volume were found. The practice shows that the composite foundation with CFG pile in high building of shallow buried depth of bedrock is safe and reliable with less construction cost and shorter construction period.