Research conclusions: Taking a special railway track in the coal mine as an example，on the basis of stability analysis， the limit height of soft soil embankment is obtained． In the case that the heightening requirements of the embankment under mining subsidence can not be met，the CFG pile can be used for reinforcing the subgrade． And based on the theoretical checking － calculation of the bearing capability of the composite subgrade，the comparative analysis of the settlement with finite － element method and the comparison with the reinforcing program of high － pressure jet grouting pile，the feasibility and safety of CFG pile for reinforcing soft foundation are tested and verified． The result shows the CFG pile is better for reinforcing soft foundation than the high － pressure jet grouting pile under the same conditions． According to the relative codes，the reinforcement design requirement with CFG pile is presented． The wide application CFG pile has the positive effect on making use of the wastes，saving the cost and protecting environment．