In a construction for handling loess collapse with lime-soil compaction pile in Zhengzhou, there was still slight collapse in some individual horizons after the treatment. By the analysis on loess collapse mechanics, principles of collapse treatment with lime-soil compaction pile and some engineering problems, it is found that the unsuitable boring method for lime-soil pile and not enough compaction impact force are the main causes. By taking impact compaction boring and increasing the weight of compact hammer for backfilling from 100kg to 200kg, the loess collapse are all eliminated.