The foundation pit works, as a comprehensive engineering project, its quality directly affects the subsequent construction; the most important factors are geotechnical and groundwater conditions, these two bring a lot of uncertainty. This paper analyzes soil seepage, settlement deformation and other issues during the excavation process of a foundation pit and puts forward a reasonable solution, it is concluded that uniaxial mixing pile is not suitable for waterproof curtain in soft soil; the completed anchors, being easy to have pre-stress loss in soft soil with severe creep deformation, should be kept detecting and tensioned for reinforcement.