This thesis analyzes the advantages of the powder jetting piles for foundation pit retaining support in the soft stratum, and shows the design and construction techniques of the powder jetting piles by field cases. The ladder style retaining wall is designed by “m” method, which prevents the retaining wall from whole slippage and hunching effectively. In the process of construction, the repetition of jetting and mixing are carried out, so the supporting and impermeability of the retaining wall are strengthened.