Numerical simulation may efficiently analyze the deformation of the envelope structure and surface settlement caused by the excavation of deep foundation pits. However, there are no common recognition for determining the parameters of the layered soil mostly used in the numerical simulation. Taking the end well section of the deep foundation pit in a subway station in Shanghai as an example, the construction process was simulated using the finite element software ABAQUS. After estimating the importance of each parameter by using orthogonal test, the sensitivity of the influence of the parameters of various soil layers on the horizontal displacement of the envelope structure was analysed. The back analysis was furthermore conducted to determine the parameters used in the finite element simulation for the pit excavation. It is shown that two parameters, i.e., the elastic modulus and Poisson's ratio, have the greatest influence on the horizontal displacement of the continuous wall in the numerical simulation. In the finite element simulation, the modulus ratios (ratios of the elastic modulus to compressive modulus) for the sludgy clay and sludgy silty clay can be taken as 3.25～3.35, those for the clay and silty clay can be taken as 3.67 and 5.69～5.81, while those for the silt and silty sand can be taken as 6.14 and 6.17～6.44. The modulus ratios for the corresponding soil layers from small to great are cohesive soil, silty soil, and sandy soil in order. The ratio of the Poisson's ratio to survey ratio for silty soil is 1.05～1.12, while those of other soil layers are 0.90～1.05.