The foundation pit of Shajing pumping station,which is with a deep silt layer and deep excavation,locates in the deep thick soft ground area and.The simulated calculation for the support scheme by adding virtual tension indicates that the internal stress bending moment can’t meet the requirement for the retaining pile of deep foundation pit stipulated in the code.So,we propose an optimized scheme for the foundation pit.By the comparative analysis of the site construction monitoring data and the calculation data,we prove the reasonableness of optimized program.