Abstract: For a high speed rail over soft soils, the post construction settlement is an important factor affecting safe operation. The Cement Fly\|ash Gravel (CFG) column composite ground improvement technique was selected to strengthen the soft soils in the high speed passenger rail project from Wuhan to Guangzhou. Based on the typical subsurface conditions, numerical analyses on the CFG column composite ground mass were conducted using the ADINA Finite Element Method. The results indicate that a maximum of 35 mm settlement would occur immediately after the soil improvement construction. This allowed development of measures to control settlement after laying the tracks. This study indicated that CFG composite ground is an effective method of soil improvement for high speed passenger rail construction. The bearing capacities and post construction settlements of the composite ground mass can meet the design requirements.