When a large deep foundation pit is constructed in a typical complex stratum with high pressurized water sand layer, the displacement response of the diaphragm wall will develop gradually and dynamically with the active loss or passive extrusion of the stratum, which will put the enclosure structure in a dangerous state once it exceeds the limit value required by the current standard. Reasonable determination of the important construction parameters of diaphragm wall under such stratigraphic conditions is essential to the fine control of deep foundation pit enclosure structure construction, and is also a prerequisite to ensure the safety and reliability of deep foundation pits and the surrounding environment. This paper uses numerical simulation to carry out orthogonal experiments, selects the elastic modulus of diaphragm wall, diaphragm wall thickness, support stiffness and support cross-sectional area as experimental factors, takes the horizontal displacement of the diaphragm wall as the safety evaluation index, and the reliability of the model was verified through on-site testing. The innovative construction parameter selection method proposed in this paper will provide a basis for the design of deep foundation pit envelope structure, and provide a reference for the design of intelligent foundation pit.