Abstract: In order to analyze the influence of soil deformation surrounding the trench of diaphragm wall during the construction period, the diaphragm wall trench, thickness 1.2 m, width 4. 5 m and depth 61.0 m, was tested before the retaining wall of foundation pit constructed in Nanjing Hexi area. The results show that soil deformation in different depths appeared different displacement degrees when the trench was excavated, and part data of monitoring were negative The soil deformation surrounding the trench had a little impact on the environment, when the single trench of the diaphragm wall was constructed.