Abstract: The design and construction of top-down construc ti on method of SMW(Soil-cement Mixed Wall)in deep pit applied for the first time in our country is introduced.The pro ject used SMW as the retaining wall fo r exterior waterproof and support,steel columns a s the bearing piles for the vertical load,and some structural beams and sl abs as the horizontal support. Furthermore, with the help of the struts hangi ng technique and spatial lute struts technique,the deepest SMW pit in our c ountry was successfully excavated.